Index: src/orca/scripts/toolkits/Gecko/script.py
===================================================================
--- src/orca/scripts/toolkits/Gecko/script.py	(revision 4626)
+++ src/orca/scripts/toolkits/Gecko/script.py	(working copy)
@@ -2782,6 +2782,16 @@
         if not self.inDocumentContent():
             return False
 
+        # If we're in something which is supposed to act like a dialog
+        # box, we should treat it just like any other dialog box and
+        # not control navigation. We see this with ARIA dialogs in
+        # which the focused entry is not an ARIA widget.
+        #
+        if self.getAncestor(orca_state.locusOfFocus,
+                            [pyatspi.ROLE_DIALOG],
+                            [pyatspi.ROLE_DOCUMENT_FRAME]):
+            return False
+
         if not self.isNavigableAria(orca_state.locusOfFocus):
             return False
 
