[orca] Ensure we don't use structural navigation in editable messages

[Joanmarie Diggs <joanied src gnome org>]

commit bea2900d3a31f539446f477f2363559e3d773fa0
Author: Joanmarie Diggs <jdiggs igalia com>
Date:   Sun Apr 20 14:19:46 2014 -0400

    Ensure we don't use structural navigation in editable messages

 src/orca/scripts/apps/Thunderbird/script.py |    8 ++++++++
 1 files changed, 8 insertions(+), 0 deletions(-)
---
diff --git a/src/orca/scripts/apps/Thunderbird/script.py b/src/orca/scripts/apps/Thunderbird/script.py
index 72c7da6..962622a 100644
--- a/src/orca/scripts/apps/Thunderbird/script.py
+++ b/src/orca/scripts/apps/Thunderbird/script.py
@@ -132,6 +132,14 @@ class Script(Gecko.Script):
 
         Gecko.Script.doWhereAmI(self,inputEvent, basicOnly)
 
+    def useStructuralNavigationModel(self):
+        """Returns True if structural navigation should be enabled here."""
+
+        if self.isEditableMessage(orca_state.locusOfFocus):
+            return False
+
+        return Gecko.Script.useStructuralNavigationModel(self)
+
     def onFocusedChanged(self, event):
         """Callback for object:state-changed:focused accessibility events."""