Index: src/orca/mag.py
===================================================================
--- src/orca/mag.py	(revision 3408)
+++ src/orca/mag.py	(working copy)
@@ -1320,7 +1320,7 @@
     - updateScreen:  Whether or not to update the screen
     """
 
-    if not _initialized:
+    if not _initialized or not isFilteringCapable():
         return
 
     if colorFilter == settings.MAG_COLOR_FILTERING_MODE_SATURATE_RED:
@@ -1352,6 +1352,18 @@
     if updateScreen:
         _zoomer.markDirty(_roi)
 
+def isFilteringCapable():
+    """Returns True if we're able to take advantage of libcolorblind's color
+    filtering.
+    """
+
+    try:
+        capable = _magnifier.supportColorblindFilters()
+    except:
+        capable = False
+
+    return capable
+
 def updateMouseTracking(newMode):
     """Updates the mouse tracking mode.
 
Index: src/orca/orca-setup.glade
===================================================================
--- src/orca/orca-setup.glade	(revision 3408)
+++ src/orca/orca-setup.glade	(working copy)
@@ -1252,8 +1252,8 @@
 				  <property name="wrap">False</property>
 				  <property name="adjustment">10 1 9999 1 10 10</property>
 				  <accessibility>
+				    <atkrelation target="speakProgressBarLabel" type="labelled-by"/>
 				    <atkrelation target="speakProgressBarUnitsLabel" type="labelled-by"/>
-				    <atkrelation target="speakProgressBarLabel" type="labelled-by"/>
 				  </accessibility>
 				  <signal name="value_changed" handler="speakProgressBarValueChanged" last_modification_time="Thu, 14 Jun 2007 15:09:00 GMT"/>
 				</widget>
@@ -3366,8 +3366,8 @@
 							  <property name="wrap">False</property>
 							  <property name="adjustment">1 24 256 1 10 10</property>
 							  <accessibility>
+							    <atkrelation target="magCursorSizeUnitsLabel" type="labelled-by"/>
 							    <atkrelation target="magCursorSizeLabel" type="labelled-by"/>
-							    <atkrelation target="magCursorSizeUnitsLabel" type="labelled-by"/>
 							  </accessibility>
 							  <signal name="value_changed" handler="magCursorSizeValueChanged" last_modification_time="Wed, 03 May 2006 15:31:48 GMT"/>
 							</widget>
@@ -3719,8 +3719,8 @@
 							  <property name="wrap">False</property>
 							  <property name="adjustment">1 1 256 1 10 10</property>
 							  <accessibility>
+							    <atkrelation target="magCrossHairSizeUnitsLabel" type="labelled-by"/>
 							    <atkrelation target="magCrossHairSizeLabel" type="labelled-by"/>
-							    <atkrelation target="magCrossHairSizeUnitsLabel" type="labelled-by"/>
 							  </accessibility>
 							  <signal name="value_changed" handler="magCrossHairSizeValueChanged" last_modification_time="Wed, 03 May 2006 15:39:23 GMT"/>
 							</widget>
@@ -4157,8 +4157,8 @@
 						  <property name="wrap">False</property>
 						  <property name="adjustment">0 0 100 1 10 10</property>
 						  <accessibility>
+						    <atkrelation target="magEdgeMarginLabel" type="labelled-by"/>
 						    <atkrelation target="magEdgeMarginUnitsLabel" type="labelled-by"/>
-						    <atkrelation target="magEdgeMarginLabel" type="labelled-by"/>
 						  </accessibility>
 						  <signal name="value_changed" handler="magEdgeMarginValueChanged" last_modification_time="Thu, 06 Dec 2007 22:57:50 GMT"/>
 						</widget>
@@ -5954,7 +5954,7 @@
 	  <property name="right_padding">0</property>
 
 	  <child>
-	    <widget class="GtkHBox" id="hbox62">
+	    <widget class="GtkHBox" id="magColorFilteringHbox">
 	      <property name="visible">True</property>
 	      <property name="homogeneous">False</property>
 	      <property name="spacing">5</property>
Index: src/orca/orca_gui_prefs.py
===================================================================
--- src/orca/orca_gui_prefs.py	(revision 3408)
+++ src/orca/orca_gui_prefs.py	(working copy)
@@ -4053,7 +4053,10 @@
         index = self.getComboBoxIndex(comboBox, filteringMode)
         comboBox.set_active(index)
 
-        if self.enableLiveUpdating:
+        enable = mag.isFilteringCapable()
+        self.get_widget("magColorFilteringHbox").set_sensitive(enable)
+
+        if enable and self.enableLiveUpdating:
             mag.setZoomerColorFilter(mode)
 
     def magColorFilteringChanged(self, widget):
