Index: src/orca/scripts/toolkits/Gecko/script.py
===================================================================
--- src/orca/scripts/toolkits/Gecko/script.py	(revision 4473)
+++ src/orca/scripts/toolkits/Gecko/script.py	(working copy)
@@ -2686,6 +2686,14 @@
                         else:
                             documentFrame = None
 
+        # Certain add-ons can interfere with the above approach. But we
+        # should have a locusOfFocus. If so look up and try to find the
+        # document frame. See bug 537303.
+        #
+        if not documentFrame:
+            documentFrame = self.getAncestor(orca_state.locusOfFocus,
+                                             [pyatspi.ROLE_DOCUMENT_FRAME],
+                                             [pyatspi.ROLE_FRAME])
         return documentFrame
 
     def getURI(self, obj):
