Index: src/orca/scripts/apps/gnome-mud.py
===================================================================
--- src/orca/scripts/apps/gnome-mud.py	(revision 3968)
+++ src/orca/scripts/apps/gnome-mud.py	(working copy)
@@ -132,8 +132,8 @@
             keyBindings.add(
                 keybindings.KeyBinding(
                     messagekey,
-                    1 << settings.MODIFIER_ORCA,
-                    1 << settings.MODIFIER_ORCA,
+                    settings.defaultModifierMask,
+                    settings.ORCA_MODIFIER_MASK,
                     self.inputEventHandlers["readPreviousMessageHandler"]))
 
         return keyBindings
Index: src/orca/scripts/apps/evolution/script.py
===================================================================
--- src/orca/scripts/apps/evolution/script.py	(revision 3968)
+++ src/orca/scripts/apps/evolution/script.py	(working copy)
@@ -180,8 +180,8 @@
         keyBindings.add(
             keybindings.KeyBinding(
                 "n",
-                1 << settings.MODIFIER_ORCA,
-                1 << settings.MODIFIER_ORCA,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["toggleReadMailHandler"]))
         return keyBindings
 
Index: src/orca/scripts/apps/gnome-terminal.py
===================================================================
--- src/orca/scripts/apps/gnome-terminal.py	(revision 3968)
+++ src/orca/scripts/apps/gnome-terminal.py	(working copy)
@@ -208,7 +208,7 @@
             keyString = orca_state.lastNonModifierKeyEvent.event_string
 
             controlPressed = orca_state.lastInputEvent.modifiers \
-                             & (1 << pyatspi.MODIFIER_CONTROL)
+                             & settings.CTRL_MODIFIER_MASK
 
             if (keyString == "Delete") or (keyString == "BackSpace"):
                 return
@@ -240,11 +240,7 @@
             # compressed string is (we choose 5 here), then output that.
             #
             wasCommand = orca_state.lastInputEvent.modifiers \
-                         & (1 << pyatspi.MODIFIER_CONTROL \
-                            | 1 << pyatspi.MODIFIER_ALT \
-                            | 1 << pyatspi.MODIFIER_META \
-                            | 1 << pyatspi.MODIFIER_META2 \
-                            | 1 << pyatspi.MODIFIER_META3)
+                         & settings.COMMAND_MODIFIER_MASK
             wasCommand = wasCommand \
                          or (keyString == "Return") \
                          or (keyString == "Tab")
Index: src/orca/scripts/apps/pidgin/script.py
===================================================================
--- src/orca/scripts/apps/pidgin/script.py	(revision 3968)
+++ src/orca/scripts/apps/pidgin/script.py	(working copy)
@@ -224,22 +224,22 @@
         keyBindings.add(
             keybindings.KeyBinding(
                 "h",
-                1 << settings.MODIFIER_ORCA,
-                1 << settings.MODIFIER_ORCA,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["togglePrefixHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "",
-                None,
-                None,
+                settings.NO_MODIFIER_MASK,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["toggleBuddyTypingHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "",
-                None,
-                None,
+                settings.NO_MODIFIER_MASK,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["toggleMessageHistoriesHandler"]))
 
         # keybindings to provide chat room message history.
@@ -249,8 +249,8 @@
             keyBindings.add(
                 keybindings.KeyBinding(
                     messageKey,
-                    1 << settings.MODIFIER_ORCA,
-                    1 << settings.MODIFIER_ORCA,
+                    settings.defaultModifierMask,
+                    settings.ORCA_MODIFIER_MASK,
                     self.inputEventHandlers["reviewMessage"]))
 
         return keyBindings
Index: src/orca/scripts/apps/soffice/script.py
===================================================================
--- src/orca/scripts/apps/soffice/script.py	(revision 3968)
+++ src/orca/scripts/apps/soffice/script.py	(working copy)
@@ -231,39 +231,39 @@
         keyBindings.add(
             keybindings.KeyBinding(
                 "a",
-                1 << settings.MODIFIER_ORCA,
-                1 << settings.MODIFIER_ORCA,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["speakInputLineHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "r",
-                1 << settings.MODIFIER_ORCA,
-                1 << settings.MODIFIER_ORCA,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["setDynamicColumnHeadersHandler"],
                 1))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "r",
-                1 << settings.MODIFIER_ORCA,
-                1 << settings.MODIFIER_ORCA,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["clearDynamicColumnHeadersHandler"],
                 2))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "c",
-                1 << settings.MODIFIER_ORCA,
-                1 << settings.MODIFIER_ORCA,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["setDynamicRowHeadersHandler"],
                 1))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "c",
-                1 << settings.MODIFIER_ORCA,
-                1 << settings.MODIFIER_ORCA,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["clearDynamicRowHeadersHandler"],
                 2))
 
@@ -1653,11 +1653,7 @@
                 keyString = orca_state.lastNonModifierKeyEvent.event_string
                 navKeys = ["Up", "Down", "Page_Up", "Page_Down", "Home", "End"]
                 wasCommand = orca_state.lastInputEvent.modifiers \
-                             & (1 << pyatspi.MODIFIER_CONTROL \
-                              | 1 << pyatspi.MODIFIER_ALT \
-                              | 1 << pyatspi.MODIFIER_META \
-                              | 1 << pyatspi.MODIFIER_META2 \
-                              | 1 << pyatspi.MODIFIER_META3)
+                             & settings.COMMAND_MODIFIER_MASK
                 weToggledIt = wasCommand and keyString not in navKeys
 
             if weToggledIt:
@@ -1856,7 +1852,7 @@
         if orca_state.lastNonModifierKeyEvent:
             event_string = orca_state.lastNonModifierKeyEvent.event_string
             isShiftKey = orca_state.lastNonModifierKeyEvent.modifiers \
-                         & (1 << pyatspi.MODIFIER_SHIFT)
+                         & settings.SHIFT_MODIFIER_MASK
         else:
             event_string = ''
             isShiftKey = False
Index: src/orca/scripts/toolkits/Gecko/script.py
===================================================================
--- src/orca/scripts/toolkits/Gecko/script.py	(revision 3968)
+++ src/orca/scripts/toolkits/Gecko/script.py	(working copy)
@@ -808,134 +808,125 @@
         arrow keys for navigating HTML content.
         """
 
-        altModMask       =  1 << pyatspi.MODIFIER_ALT
-        controlModMask   =  1 << pyatspi.MODIFIER_CONTROL
-        shiftAltModMask  = (1 << pyatspi.MODIFIER_SHIFT |
-                            1 << pyatspi.MODIFIER_ALT)
-        fullModMask      = (1 << pyatspi.MODIFIER_SHIFT |
-                            1 << pyatspi.MODIFIER_ALT |
-                            1 << pyatspi.MODIFIER_CONTROL |
-                            1 << settings.MODIFIER_ORCA)
-
         keyBindings = keybindings.KeyBindings()
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "Right",
-                fullModMask,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["goNextCharacterHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "Left",
-                fullModMask,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["goPreviousCharacterHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "Right",
-                fullModMask,
-                controlModMask,
+                settings.defaultModifierMask,
+                settings.CTRL_MODIFIER_MASK,
                 self.inputEventHandlers["goNextWordHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "Left",
-                fullModMask,
-                controlModMask,
+                settings.defaultModifierMask,
+                settings.CTRL_MODIFIER_MASK,
                 self.inputEventHandlers["goPreviousWordHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "Up",
-                fullModMask,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["goPreviousLineHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "Down",
-                fullModMask,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["goNextLineHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "Down",
-                fullModMask,
-                altModMask,
+                settings.defaultModifierMask,
+                settings.ALT_MODIFIER_MASK,
                 self.inputEventHandlers["expandComboBoxHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "Right",
-                fullModMask,
-                shiftAltModMask,
+                settings.defaultModifierMask,
+                settings.SHIFT_ALT_MODIFIER_MASK,
                 self.inputEventHandlers["goCellRightHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "Left",
-                fullModMask,
-                shiftAltModMask,
+                settings.defaultModifierMask,
+                settings.SHIFT_ALT_MODIFIER_MASK,
                 self.inputEventHandlers["goCellLeftHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "Up",
-                fullModMask,
-                shiftAltModMask,
+                settings.defaultModifierMask,
+                settings.SHIFT_ALT_MODIFIER_MASK,
                 self.inputEventHandlers["goCellUpHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "Down",
-                fullModMask,
-                shiftAltModMask,
+                settings.defaultModifierMask,
+                settings.SHIFT_ALT_MODIFIER_MASK,
                 self.inputEventHandlers["goCellDownHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "Home",
-                fullModMask,
-                shiftAltModMask,
+                settings.defaultModifierMask,
+                settings.SHIFT_ALT_MODIFIER_MASK,
                 self.inputEventHandlers["goCellFirstHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "End",
-                fullModMask,
-                shiftAltModMask,
+                settings.defaultModifierMask,
+                settings.SHIFT_ALT_MODIFIER_MASK,
                 self.inputEventHandlers["goCellLastHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "Home",
-                fullModMask,
-                controlModMask,
+                settings.defaultModifierMask,
+                settings.CTRL_MODIFIER_MASK,
                 self.inputEventHandlers["goTopOfFileHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "End",
-                fullModMask,
-                controlModMask,
+                settings.defaultModifierMask,
+                settings.CTRL_MODIFIER_MASK,
                 self.inputEventHandlers["goBottomOfFileHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "Home",
-                fullModMask,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["goBeginningOfLineHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "End",
-                fullModMask,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["goEndOfLineHandler"]))
 
         return keyBindings
@@ -946,255 +937,237 @@
         Returns an instance of keybindings.KeyBindings.
         """
 
-        orcaModMask      =  1 << settings.MODIFIER_ORCA
-        shiftModMask     =  1 << pyatspi.MODIFIER_SHIFT
-        orcaShiftModMask = (1 << settings.MODIFIER_ORCA |
-                            1 << pyatspi.MODIFIER_SHIFT)
-        fullModMask      = (1 << pyatspi.MODIFIER_SHIFT |
-                            1 << pyatspi.MODIFIER_ALT |
-                            1 << pyatspi.MODIFIER_CONTROL |
-                            1 << settings.MODIFIER_ORCA)
-
         keyBindings = default.Script.getKeyBindings(self)
 
-        # NOTE: We include ALT and CONTROL in all the bindings below so as
-        # to not conflict with menu and other mnemonics.
-
         keyBindings.add(
             keybindings.KeyBinding(
                 "h",
-                fullModMask,
-                shiftModMask,
+                settings.defaultModifierMask,
+                settings.SHIFT_MODIFIER_MASK,
                 self.inputEventHandlers["goPreviousHeadingHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "h",
-                fullModMask,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["goNextHeadingHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "1",
-                fullModMask,
-                shiftModMask,
+                settings.defaultModifierMask,
+                settings.SHIFT_MODIFIER_MASK,
                 self.inputEventHandlers["goPreviousHeading1Handler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "1",
-                fullModMask,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["goNextHeading1Handler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "2",
-                fullModMask,
-                shiftModMask,
+                settings.defaultModifierMask,
+                settings.SHIFT_MODIFIER_MASK,
                 self.inputEventHandlers["goPreviousHeading2Handler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "2",
-                fullModMask,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["goNextHeading2Handler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "3",
-                fullModMask,
-                shiftModMask,
+                settings.defaultModifierMask,
+                settings.SHIFT_MODIFIER_MASK,
                 self.inputEventHandlers["goPreviousHeading3Handler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "3",
-                fullModMask,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["goNextHeading3Handler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "4",
-                fullModMask,
-                shiftModMask,
+                settings.defaultModifierMask,
+                settings.SHIFT_MODIFIER_MASK,
                 self.inputEventHandlers["goPreviousHeading4Handler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "4",
-                fullModMask,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["goNextHeading4Handler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "5",
-                fullModMask,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["goNextHeading5Handler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "5",
-                fullModMask,
-                shiftModMask,
+                settings.defaultModifierMask,
+                settings.SHIFT_MODIFIER_MASK,
                 self.inputEventHandlers["goPreviousHeading5Handler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "6",
-                fullModMask,
-                shiftModMask,
+                settings.defaultModifierMask,
+                settings.SHIFT_MODIFIER_MASK,
                 self.inputEventHandlers["goPreviousHeading6Handler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "6",
-                fullModMask,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["goNextHeading6Handler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "o",
-                fullModMask,
-                shiftModMask,
+                settings.defaultModifierMask,
+                settings.SHIFT_MODIFIER_MASK,
                 self.inputEventHandlers["goPreviousChunkHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "o",
-                fullModMask,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["goNextChunkHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "l",
-                fullModMask,
-                shiftModMask,
+                settings.defaultModifierMask,
+                settings.SHIFT_MODIFIER_MASK,
                 self.inputEventHandlers["goPreviousListHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "l",
-                fullModMask,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["goNextListHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "i",
-                fullModMask,
-                shiftModMask,
+                settings.defaultModifierMask,
+                settings.SHIFT_MODIFIER_MASK,
                 self.inputEventHandlers["goPreviousListItemHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "i",
-                fullModMask,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["goNextListItemHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "u",
-                fullModMask,
-                shiftModMask,
+                settings.defaultModifierMask,
+                settings.SHIFT_MODIFIER_MASK,
                 self.inputEventHandlers["goPreviousUnvisitedLinkHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "u",
-                fullModMask,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["goNextUnvisitedLinkHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "v",
-                fullModMask,
-                shiftModMask,
+                settings.defaultModifierMask,
+                settings.SHIFT_MODIFIER_MASK,
                 self.inputEventHandlers["goPreviousVisitedLinkHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "v",
-                fullModMask,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["goNextVisitedLinkHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "Tab",
-                fullModMask,
-                orcaShiftModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_SHIFT_MODIFIER_MASK,
                 self.inputEventHandlers["goPreviousFormFieldHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "Tab",
-                fullModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["goNextFormFieldHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "q",
-                fullModMask,
-                shiftModMask,
+                settings.defaultModifierMask,
+                settings.SHIFT_MODIFIER_MASK,
                 self.inputEventHandlers["goPreviousBlockquoteHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "q",
-                fullModMask,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["goNextBlockquoteHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "t",
-                fullModMask,
-                shiftModMask,
+                settings.defaultModifierMask,
+                settings.SHIFT_MODIFIER_MASK,
                 self.inputEventHandlers["goPreviousTableHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "t",
-                fullModMask,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["goNextTableHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "r",
-                (1 << pyatspi.MODIFIER_SHIFT \
-                 | 1 << pyatspi.MODIFIER_ALT \
-                 | 1 << pyatspi.MODIFIER_CONTROL),
-                1 << pyatspi.MODIFIER_SHIFT,
+                settings.defaultModifierMask,
+                settings.SHIFT_MODIFIER_MASK,
                 self.inputEventHandlers["goPreviousLiveRegion"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "r",
-                (1 << pyatspi.MODIFIER_SHIFT \
-                 | 1 << pyatspi.MODIFIER_ALT \
-                 | 1 << pyatspi.MODIFIER_CONTROL),
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["goNextLiveRegion"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "y",
-                (1 << pyatspi.MODIFIER_SHIFT \
-                 | 1 << pyatspi.MODIFIER_ALT \
-                 | 1 << pyatspi.MODIFIER_CONTROL),
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["goLastLiveRegion"]))
 
         # keybindings to provide chat room message history.
@@ -1203,68 +1176,64 @@
             keyBindings.add(
                 keybindings.KeyBinding(
                     messageKey,
-                    1 << settings.MODIFIER_ORCA,
-                    1 << settings.MODIFIER_ORCA,
+                    settings.defaultModifierMask,
+                    settings.ORCA_MODIFIER_MASK,
                     self.inputEventHandlers["reviewLiveAnnouncement"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "backslash",
-                (1 << pyatspi.MODIFIER_SHIFT \
-                 | 1 << pyatspi.MODIFIER_ALT \
-                 | 1 << pyatspi.MODIFIER_CONTROL),
-                1 << pyatspi.MODIFIER_SHIFT,
+                settings.defaultModifierMask,
+                settings.SHIFT_MODIFIER_MASK,
                 self.inputEventHandlers["setLivePolitenessOff"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "backslash",
-                fullModMask,
-                orcaShiftModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_SHIFT_MODIFIER_MASK,
                 self.inputEventHandlers["monitorLiveRegions"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "backslash",
-                (1 << pyatspi.MODIFIER_SHIFT \
-                 | 1 << pyatspi.MODIFIER_ALT \
-                 | 1 << pyatspi.MODIFIER_CONTROL),
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["advanceLivePoliteness"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "F12",
-                fullModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["toggleCaretNavigationHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "SunF37",
-                fullModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["toggleCaretNavigationHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "z",
-                fullModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["toggleStructuralNavigationHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "Right",
-                fullModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["goNextObjectInOrderHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "Left",
-                fullModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["goPreviousObjectInOrderHandler"]))
 
         if script_settings.controlCaretNavigation:
@@ -1279,15 +1248,15 @@
         keyBindings.add(
             keybindings.KeyBinding(
                 None,
-                0,
-                0,
+                settings.NO_MODIFIER_MASK,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["goPreviousLandmark"]))
 
         keyBindings.add(
              keybindings.KeyBinding(
                 None,
-                0,
-                0,
+                settings.NO_MODIFIER_MASK,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["goNextLandmark"]))
 
         return keyBindings
@@ -3426,7 +3395,7 @@
                and not self._autocompleteVisible:
                 weHandleIt = keyboardEvent.event_string in ["Up", "Down"]
 
-        elif keyboardEvent.modifiers & (1 << pyatspi.MODIFIER_ALT):
+        elif keyboardEvent.modifiers & settings.ALT_MODIFIER_MASK:
             # Alt+Down Arrow is the Firefox command to expand/collapse the
             # *currently focused* combo box.  When Orca is controlling the
             # caret, it is possible to navigate into a combo box *without
@@ -3492,7 +3461,7 @@
         #
         if isinstance(orca_state.lastInputEvent, input_event.KeyboardEvent):
             mods = orca_state.lastInputEvent.modifiers
-            isOrcaKey = mods & (1 << settings.MODIFIER_ORCA)
+            isOrcaKey = mods & settings.ORCA_MODIFIER_MASK
             if isOrcaKey:
                 return True
 
Index: src/orca/settings.py
===================================================================
--- src/orca/settings.py	(revision 3968)
+++ src/orca/settings.py	(working copy)
@@ -80,6 +80,8 @@
 except:
     gconfClient = None
 
+import pyatspi
+
 import debug
 from acss import ACSS
 from orca_i18n import _           # for gettext support
@@ -1006,3 +1008,47 @@
 # Maximum allowed drift while pointer is dwelling in mouse review mode.
 # 
 mouseDwellMaxDrift = 3
+
+# The different modifiers/modifier masks associated with keybindings
+#
+NO_MODIFIER_MASK              =  0
+ALT_MODIFIER_MASK             =  1 << pyatspi.MODIFIER_ALT
+CTRL_MODIFIER_MASK            =  1 << pyatspi.MODIFIER_CONTROL
+ORCA_MODIFIER_MASK            =  1 << MODIFIER_ORCA
+ORCA_ALT_MODIFIER_MASK        = (1 << MODIFIER_ORCA |
+                                 1 << pyatspi.MODIFIER_ALT)
+ORCA_CTRL_MODIFIER_MASK       = (1 << MODIFIER_ORCA |
+                                 1 << pyatspi.MODIFIER_CONTROL)
+ORCA_CTRL_ALT_MODIFIER_MASK   = (1 << MODIFIER_ORCA |
+                                 1 << pyatspi.MODIFIER_CONTROL |
+                                 1 << pyatspi.MODIFIER_ALT)
+ORCA_SHIFT_MODIFIER_MASK      = (1 << MODIFIER_ORCA |
+                                 1 << pyatspi.MODIFIER_SHIFT)
+SHIFT_MODIFIER_MASK           =  1 << pyatspi.MODIFIER_SHIFT
+SHIFT_ALT_MODIFIER_MASK       = (1 << pyatspi.MODIFIER_SHIFT |
+                                 1 << pyatspi.MODIFIER_ALT)
+COMMAND_MODIFIER_MASK         = (1 << pyatspi.MODIFIER_ALT |
+                                 1 << pyatspi.MODIFIER_CONTROL |
+                                 1 << pyatspi.MODIFIER_META2 |
+                                 1 << pyatspi.MODIFIER_META3)
+NON_LOCKING_MODIFIER_MASK     = (1 << pyatspi.MODIFIER_SHIFT |
+                                 1 << pyatspi.MODIFIER_ALT |
+                                 1 << pyatspi.MODIFIER_CONTROL |
+                                 1 << pyatspi.MODIFIER_META2 |
+                                 1 << pyatspi.MODIFIER_META3 |
+                                 1 << MODIFIER_ORCA)
+ALL_BUT_NUMLOCK_MODIFIER_MASK = (1 << MODIFIER_ORCA |
+                                 1 << pyatspi.MODIFIER_SHIFT |
+                                 1 << pyatspi.MODIFIER_SHIFTLOCK |
+                                 1 << pyatspi.MODIFIER_CONTROL |
+                                 1 << pyatspi.MODIFIER_ALT |
+                                 1 << pyatspi.MODIFIER_META2 |
+                                 1 << pyatspi.MODIFIER_META3)
+
+# The 2nd parameter used when creating a keybinding refers to the
+# modifiers "we care about."  We typically care about all of the
+# modifiers which are not locking keys because we want to avoid
+# conflicts with other commands, such as Orca's command for moving
+# among headings (H) and the Help menu (Alt+H).
+#
+defaultModifierMask = NON_LOCKING_MODIFIER_MASK
Index: src/orca/orca.py
===================================================================
--- src/orca/orca.py	(revision 3968)
+++ src/orca/orca.py	(working copy)
@@ -748,7 +748,7 @@
 
     if _orcaModifierPressed:
         keyboardEvent.modifiers = keyboardEvent.modifiers \
-                                  | (1 << settings.MODIFIER_ORCA)
+                                  | settings.ORCA_MODIFIER_MASK
 
     orca_state.lastInputEvent = keyboardEvent
 
Index: src/orca/default.py
===================================================================
--- src/orca/default.py	(revision 3968)
+++ src/orca/default.py	(working copy)
@@ -1004,386 +1004,383 @@
         numeric keypad for focus tracking and flat review.
         """
 
-        orcaModMask      = 1 << settings.MODIFIER_ORCA
-        orcaShiftModMask = (1 << settings.MODIFIER_ORCA |
-                            1 << pyatspi.MODIFIER_SHIFT)
         keyBindings = keybindings.KeyBindings()
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_Divide",
-                0,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["leftClickReviewItemHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_Multiply",
-                0,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["rightClickReviewItemHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_Subtract",
-                0,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["toggleFlatReviewModeHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_Add",
-                0,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["sayAllHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_Enter",
-                orcaModMask,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["whereAmIBasicHandler"],
                 1))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_Enter",
-                orcaModMask,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["whereAmIDetailedHandler"],
                 2))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_Enter",
-                orcaModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["getTitleHandler"],
                 1))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_Enter",
-                orcaModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["getStatusBarHandler"],
                 2))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_Delete",
-                orcaModMask,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["findHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_Delete",
-                orcaShiftModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["findNextHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_Delete",
-                orcaShiftModMask,
-                orcaShiftModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_SHIFT_MODIFIER_MASK,
                 self.inputEventHandlers["findPreviousHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_7",
-                orcaModMask,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["reviewPreviousLineHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_Home",
-                orcaModMask,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["reviewPreviousLineHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_7",
-                orcaModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["reviewHomeHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_Home",
-                orcaModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["reviewHomeHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_8",
-                0,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["reviewCurrentLineHandler"],
                 1))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_8",
-                0,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["reviewSpellCurrentLineHandler"],
                 2))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_8",
-                0,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["reviewPhoneticCurrentLineHandler"],
                 3))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_Up",
-                0,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["reviewCurrentLineHandler"],
                 1))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_Up",
-                0,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["reviewSpellCurrentLineHandler"],
                 2))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_Up",
-                0,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["reviewPhoneticCurrentLineHandler"],
                 3))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_9",
-                orcaModMask,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["reviewNextLineHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_Page_Up",
-                orcaModMask,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["reviewNextLineHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_9",
-                orcaModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["reviewEndHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_Page_Up",
-                orcaModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["reviewEndHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_4",
-                orcaModMask,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["reviewPreviousItemHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_Left",
-                orcaModMask,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["reviewPreviousItemHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_4",
-                orcaModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["reviewAboveHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_Left",
-                orcaModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["reviewAboveHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_5",
-                orcaModMask,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["reviewCurrentItemHandler"],
                 1))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_5",
-                orcaModMask,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["reviewSpellCurrentItemHandler"],
                 2))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_5",
-                orcaModMask,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["reviewPhoneticCurrentItemHandler"],
                 3))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_Begin",
-                orcaModMask,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["reviewCurrentItemHandler"],
                 1))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_Begin",
-                orcaModMask,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["reviewSpellCurrentItemHandler"],
                 2))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_Begin",
-                orcaModMask,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["reviewPhoneticCurrentItemHandler"],
                 3))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_5",
-                orcaModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["reviewCurrentAccessibleHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_Begin",
-                orcaModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["reviewCurrentAccessibleHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_6",
-                orcaModMask,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["reviewNextItemHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_Right",
-                orcaModMask,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["reviewNextItemHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_6",
-                orcaModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["reviewBelowHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_Right",
-                orcaModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["reviewBelowHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_1",
-                orcaModMask,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["reviewPreviousCharacterHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_End",
-                orcaModMask,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["reviewPreviousCharacterHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_1",
-                orcaModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["reviewEndOfLineHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_End",
-                orcaModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["reviewEndOfLineHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_2",
-                0,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["reviewCurrentCharacterHandler"],
                 1))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_2",
-                0,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["reviewSpellCurrentCharacterHandler"],
                 2))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_Down",
-                0,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["reviewCurrentCharacterHandler"],
                 1))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_Down",
-                0,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["reviewSpellCurrentCharacterHandler"],
                 2))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_3",
-                0,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["reviewNextCharacterHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "KP_Page_Down",
-                0,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["reviewNextCharacterHandler"]))
 
         return keyBindings
@@ -1393,238 +1390,235 @@
         the main keyboard keys for focus tracking and flat review.
         """
 
-        orcaModMask        = 1 << settings.MODIFIER_ORCA
-        orcaControlModMask = (1 << settings.MODIFIER_ORCA |
-                              1 << pyatspi.MODIFIER_CONTROL)
         keyBindings = keybindings.KeyBindings()
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "7",
-                orcaModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["leftClickReviewItemHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "8",
-                orcaModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["rightClickReviewItemHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "p",
-                orcaModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["toggleFlatReviewModeHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "semicolon",
-                orcaModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["sayAllHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "Return",
-                orcaModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["whereAmIBasicHandler"],
                 1))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "Return",
-                orcaModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["whereAmIDetailedHandler"],
                 2))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "slash",
-                orcaModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["getTitleHandler"],
                 1))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "slash",
-                orcaModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["getStatusBarHandler"],
                 2))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "bracketleft",
-                orcaModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["findHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "bracketright",
-                orcaControlModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["findNextHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "bracketright",
-                orcaControlModMask,
-                orcaControlModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_CTRL_MODIFIER_MASK,
                 self.inputEventHandlers["findPreviousHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "u",
-                orcaControlModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["reviewPreviousLineHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "u",
-                orcaControlModMask,
-                orcaControlModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_CTRL_MODIFIER_MASK,
                 self.inputEventHandlers["reviewHomeHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "i",
-                orcaModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["reviewCurrentLineHandler"],
                 1))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "i",
-                orcaModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["reviewSpellCurrentLineHandler"],
                 2))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "i",
-                orcaModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["reviewPhoneticCurrentLineHandler"],
                 3))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "o",
-                orcaControlModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["reviewNextLineHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "o",
-                orcaControlModMask,
-                orcaControlModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_CTRL_MODIFIER_MASK,
                 self.inputEventHandlers["reviewEndHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "j",
-                orcaControlModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["reviewPreviousItemHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "j",
-                orcaControlModMask,
-                orcaControlModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_CTRL_MODIFIER_MASK,
                 self.inputEventHandlers["reviewAboveHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "k",
-                orcaControlModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["reviewCurrentItemHandler"],
                 1))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "k",
-                orcaControlModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["reviewSpellCurrentItemHandler"],
                 2))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "k",
-                orcaControlModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["reviewPhoneticCurrentItemHandler"],
                 3))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "k",
-                orcaControlModMask,
-                orcaControlModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_CTRL_MODIFIER_MASK,
                 self.inputEventHandlers["reviewCurrentAccessibleHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "l",
-                orcaControlModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["reviewNextItemHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "l",
-                orcaControlModMask,
-                orcaControlModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_CTRL_MODIFIER_MASK,
                 self.inputEventHandlers["reviewBelowHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "m",
-                orcaControlModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["reviewPreviousCharacterHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "m",
-                orcaControlModMask,
-                orcaControlModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_CTRL_MODIFIER_MASK,
                 self.inputEventHandlers["reviewEndOfLineHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "comma",
-                orcaModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["reviewCurrentCharacterHandler"],
                 1))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "comma",
-                orcaModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["reviewSpellCurrentCharacterHandler"],
                 2))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "period",
-                orcaModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["reviewNextCharacterHandler"]))
 
         return keyBindings
@@ -1635,21 +1629,6 @@
         Returns an instance of keybindings.KeyBindings.
         """
 
-        orcaModMask           = 1 << settings.MODIFIER_ORCA
-        orcaShiftModMask      = (1 << settings.MODIFIER_ORCA |
-                                 1 << pyatspi.MODIFIER_SHIFT)
-        orcaControlModMask    = (1 << settings.MODIFIER_ORCA |
-                                 1 << pyatspi.MODIFIER_CONTROL)
-        orcaAltModMask        = (1 << settings.MODIFIER_ORCA |
-                                 1 << pyatspi.MODIFIER_ALT)
-        orcaShiftAltModMask   = (1 << settings.MODIFIER_ORCA |
-                                 1 << pyatspi.MODIFIER_ALT |
-                                 1 << pyatspi.MODIFIER_SHIFT)
-        orcaControlAltModMask = (1 << settings.MODIFIER_ORCA |
-                                 1 << pyatspi.MODIFIER_CONTROL |
-                                 1 << pyatspi.MODIFIER_ALT)
-        shiftAltModMask       = (1 << pyatspi.MODIFIER_SHIFT |
-                                 1 << pyatspi.MODIFIER_ALT)
         keyBindings = script.Script.getKeyBindings(self)
 
         if settings.keyboardLayout == settings.GENERAL_KEYBOARD_LAYOUT_DESKTOP:
@@ -1662,92 +1641,92 @@
         keyBindings.add(
             keybindings.KeyBinding(
                 "Num_Lock",
-                orcaModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["showZonesHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "F11",
-                orcaModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["toggleTableCellReadModeHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "SunF36",
-                orcaModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["toggleTableCellReadModeHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "f",
-                orcaModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["readCharAttributesHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "h",
-                orcaModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["enterLearnModeHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "q",
-                orcaModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["shutdownHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "space",
-                orcaControlModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["preferencesSettingsHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "space",
-                orcaControlModMask,
-                orcaControlModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_CTRL_MODIFIER_MASK,
                 self.inputEventHandlers["appPreferencesSettingsHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "s",
-                orcaModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["toggleSilenceSpeechHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "End",
-                orcaControlAltModMask,
-                orcaControlAltModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_CTRL_ALT_MODIFIER_MASK,
                 self.inputEventHandlers["listAppsHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "Home",
-                orcaControlAltModMask,
-                orcaControlAltModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_CTRL_ALT_MODIFIER_MASK,
                 self.inputEventHandlers["reportScriptInfoHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "Page_Up",
-                orcaControlAltModMask,
-                orcaControlAltModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_CTRL_ALT_MODIFIER_MASK,
                 self.inputEventHandlers["printAncestryHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 "Page_Down",
-                orcaControlAltModMask,
-                orcaControlAltModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_CTRL_ALT_MODIFIER_MASK,
                 self.inputEventHandlers["printHierarchyHandler"]))
 
         #####################################################################
@@ -1759,22 +1738,22 @@
         keyBindings.add(
             keybindings.KeyBinding(
                 "b",
-                orcaShiftAltModMask,
-                orcaAltModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_ALT_MODIFIER_MASK,
                 self.inputEventHandlers["saveBookmarks"]))
         # key binding to move to the previous bookmark
         keyBindings.add(
             keybindings.KeyBinding(
                 "b",
-                orcaShiftAltModMask,
-                orcaShiftModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_SHIFT_MODIFIER_MASK,
                 self.inputEventHandlers["goToPrevBookmark"]))
         # key binding to move to the next bookmark
         keyBindings.add(
             keybindings.KeyBinding(
                 "b",
-                orcaShiftAltModMask,
-                orcaModMask,
+                settings.defaultModifierMask,
+                settings.ORCA_MODIFIER_MASK,
                 self.inputEventHandlers["goToNextBookmark"]))
 
         # key bindings for '1' through '6' for relevant commands
@@ -1783,24 +1762,24 @@
             keyBindings.add(
                 keybindings.KeyBinding(
                     str(key),
-                    orcaShiftAltModMask,
-                    orcaAltModMask,
+                    settings.defaultModifierMask,
+                    settings.ORCA_ALT_MODIFIER_MASK,
                     self.inputEventHandlers["addBookmark"]))
 
             # 'Go to bookmark' key bindings
             keyBindings.add(
                 keybindings.KeyBinding(
                     str(key),
-                    orcaShiftAltModMask,
-                    orcaModMask,
+                    settings.defaultModifierMask,
+                    settings.ORCA_MODIFIER_MASK,
                     self.inputEventHandlers["goToBookmark"]))
 
             # key binding for WhereAmI information with respect to root acc
             keyBindings.add(
                 keybindings.KeyBinding(
                     str(key),
-                    orcaShiftAltModMask,
-                    shiftAltModMask,
+                    settings.defaultModifierMask,
+                    settings.SHIFT_ALT_MODIFIER_MASK,
                     self.inputEventHandlers["bookmarkCurrentWhereAmI"]))
 
         #####################################################################
@@ -1812,114 +1791,114 @@
         keyBindings.add(
             keybindings.KeyBinding(
                 None,
-                0,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["reportScriptInfoHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 None,
-                0,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["cycleDebugLevelHandler"]))
 
         if settings.debugMemoryUsage:
             keyBindings.add(
                 keybindings.KeyBinding(
                     None,
-                    0,
-                    0,
+                    settings.NO_MODIFIER_MASK,
+                    settings.NO_MODIFIER_MASK,
                     self.inputEventHandlers["printMemoryUsageHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 None,
-                0,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["decreaseSpeechRateHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 None,
-                0,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["increaseSpeechRateHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 None,
-                0,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["decreaseSpeechPitchHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 None,
-                0,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["increaseSpeechPitchHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 None,
-                0,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["toggleColorEnhancementsHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 None,
-                0,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["toggleMouseEnhancementsHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 None,
-                0,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["increaseMagnificationHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 None,
-                0,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["decreaseMagnificationHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 None,
-                0,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["toggleMagnifierHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 None,
-                0,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["cycleZoomerTypeHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 None,
-                0,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["panBrailleLeftHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 None,
-                0,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["panBrailleRightHandler"]))
 
         keyBindings.add(
             keybindings.KeyBinding(
                 None,
-                0,
-                0,
+                settings.defaultModifierMask,
+                settings.NO_MODIFIER_MASK,
                 self.inputEventHandlers["toggleMouseReviewHandler"]))
 
         keyBindings = settings.overrideKeyBindings(self, keyBindings)
@@ -2305,8 +2284,7 @@
         # caret is (i.e. the selected character).
         #
         mods = orca_state.lastInputEvent.modifiers
-        shiftMask = 1 << pyatspi.MODIFIER_SHIFT
-        if (mods & shiftMask) \
+        if (mods & settings.SHIFT_MODIFIER_MASK) \
             and orca_state.lastNonModifierKeyEvent.event_string == "Right":
             startOffset = offset-1
             endOffset = offset
@@ -3244,8 +3222,8 @@
 
         keyString = orca_state.lastNonModifierKeyEvent.event_string
         mods = orca_state.lastInputEvent.modifiers
-        isControlKey = mods & (1 << pyatspi.MODIFIER_CONTROL)
-        isShiftKey = mods & (1 << pyatspi.MODIFIER_SHIFT)
+        isControlKey = mods & settings.CTRL_MODIFIER_MASK
+        isShiftKey = mods & settings.SHIFT_MODIFIER_MASK
         lastPos = self.pointOfReference.get("lastCursorPosition")
         hasLastPos = (lastPos != None)
 
@@ -3458,7 +3436,7 @@
 
         keyString = orca_state.lastNonModifierKeyEvent.event_string
         controlPressed = orca_state.lastInputEvent.modifiers \
-                         & (1 << pyatspi.MODIFIER_CONTROL)
+                         & settings.CTRL_MODIFIER_MASK
         text = event.source.queryText()
         if keyString == "BackSpace":
             # Speak the character that has just been deleted.
@@ -3562,11 +3540,7 @@
             wasAutoComplete = (event.source.getRole() == pyatspi.ROLE_TEXT and \
                                event.source.queryText().getNSelections())
             wasCommand = orca_state.lastInputEvent.modifiers \
-                         & (1 << pyatspi.MODIFIER_CONTROL \
-                            | 1 << pyatspi.MODIFIER_ALT \
-                            | 1 << pyatspi.MODIFIER_META \
-                            | 1 << pyatspi.MODIFIER_META2 \
-                            | 1 << pyatspi.MODIFIER_META3)
+                         & settings.COMMAND_MODIFIER_MASK
             if (text == " " and keyString == "space") \
                 or (text == keyString):
                 pass
@@ -3677,7 +3651,7 @@
                 else:
                     keyString = None
                 mods = orca_state.lastInputEvent.modifiers
-                isControlKey = mods & (1 << pyatspi.MODIFIER_CONTROL)
+                isControlKey = mods & settings.CTRL_MODIFIER_MASK
                 state = orca_state.locusOfFocus.getState()
                 announceState = False
 
@@ -3840,8 +3814,7 @@
         offset = text.caretOffset
 
         mods = orca_state.lastInputEvent.modifiers
-        shiftMask = 1 << pyatspi.MODIFIER_SHIFT
-        if (mods & shiftMask) \
+        if (mods & settings.SHIFT_MODIFIER_MASK) \
             and orca_state.lastNonModifierKeyEvent.event_string == "Right":
             startOffset = offset-1
             endOffset = offset
@@ -6987,8 +6960,8 @@
             eventStr = None
             mods = 0
 
-        isControlKey = mods & (1 << pyatspi.MODIFIER_CONTROL)
-        isShiftKey = mods & (1 << pyatspi.MODIFIER_SHIFT)
+        isControlKey = mods & settings.CTRL_MODIFIER_MASK
+        isShiftKey = mods & settings.SHIFT_MODIFIER_MASK
         selectedText = (text.getNSelections() != 0)
 
         specialCaseFound = False
Index: src/orca/input_event.py
===================================================================
--- src/orca/input_event.py	(revision 3968)
+++ src/orca/input_event.py	(working copy)
@@ -29,7 +29,6 @@
 __copyright__ = "Copyright (c) 2005-2008 Sun Microsystems Inc."
 __license__   = "LGPL"
 
-import pyatspi
 import debug
 import settings
 import time
@@ -70,7 +69,7 @@
         # mapping ASCII control characters to UTF-8.]]]
         #
         event_string = event.event_string
-        if (event.modifiers & (1 << pyatspi.MODIFIER_CONTROL)) \
+        if (event.modifiers & settings.CTRL_MODIFIER_MASK) \
             and (not event.is_text) and (len(event_string) == 1):
             value = ord(event.event_string[0])
             if value < 32:
@@ -78,15 +77,8 @@
 
         # Filter out the NUMLOCK modifier -- it always causes problems.
         #
-        mask = (1 << settings.MODIFIER_ORCA |
-                1 << pyatspi.MODIFIER_SHIFT |
-                1 << pyatspi.MODIFIER_SHIFTLOCK |
-                1 << pyatspi.MODIFIER_CONTROL |
-                1 << pyatspi.MODIFIER_ALT |
-                1 << pyatspi.MODIFIER_META |
-                1 << pyatspi.MODIFIER_META2 |
-                1 << pyatspi.MODIFIER_META3)
-        event.modifiers = event.modifiers & mask
+        event.modifiers = event.modifiers \
+                          & settings.ALL_BUT_NUMLOCK_MODIFIER_MASK
 
         InputEvent.__init__(self, KEYBOARD_EVENT)
         self.type = event.type
Index: src/orca/keybindings.py
===================================================================
--- src/orca/keybindings.py	(revision 3968)
+++ src/orca/keybindings.py	(working copy)
@@ -153,7 +153,7 @@
     """
 
     text = ""
-    if mods & (1 << settings.MODIFIER_ORCA):
+    if mods & settings.ORCA_MODIFIER_MASK:
         text += _("Orca") + "+"
     #if mods & (1 << pyatspi.MODIFIER_NUMLOCK):
     #    text += _("Num_Lock") + "+"
@@ -174,12 +174,12 @@
         text += _("Meta2") + "+"
     #if mods & (1 << pyatspi.MODIFIER_META):
     #    text += _("Meta") + "+"
-    if mods & (1 << pyatspi.MODIFIER_ALT):
+    if mods & settings.ALT_MODIFIER_MASK:
         # Translators: this is presented in a GUI to represent the
         # "left alt" modifier.
         #
         text += _("Alt_L") + "+"
-    if mods & (1 << pyatspi.MODIFIER_CONTROL):
+    if mods & settings.CTRL_MODIFIER_MASK:
         # Translators: this is presented in a GUI to represent the
         # "control" modifier.
         #
@@ -189,7 +189,7 @@
         # "caps lock" modifier.
         #
         text += _("Caps_Lock") + "+"
-    if mods & (1 << pyatspi.MODIFIER_SHIFT):
+    if mods & settings.SHIFT_MODIFIER_MASK:
         # Translators: this is presented in a GUI to represent the
         # "shift " modifier.
         #
