don't traceback with GTK < 2.18

src/message_textview.py

@@ -306,6 +306,13 @@ class MessageTextView(gtk.TextView):
         if self.undo_list:
             _buffer.set_text(self.undo_list.pop())
         self.undo_pressed = True
+        
+    def get_sensitive(self):
+        # get sensitive is not in GTK < 2.18
+        try:
+            super(MessageTextView, self).get_sensitive()
+        except AttributeError:
+            return self.get_property('sensitive')
 
 # We register depending on keysym and modifier some bindings
 # but we also pass those as param so we can construct fake Event