[meld] filediff: Fix sensitivity setting for Open External action in FileDiff

[Kai Willadsen <kaiw src gnome org>]

commit 8b7ce5e15f6746d127b165a28d704fe46036086e
Author: Kai Willadsen <kai willadsen gmail com>
Date:   Sat May 3 07:59:12 2014 +1000

    filediff: Fix sensitivity setting for Open External action in FileDiff

 meld/filediff.py |   10 ++++++++++
 1 files changed, 10 insertions(+), 0 deletions(-)
---
diff --git a/meld/filediff.py b/meld/filediff.py
index 1dee2d6..141d4bd 100644
--- a/meld/filediff.py
+++ b/meld/filediff.py
@@ -774,16 +774,26 @@ class FileDiff(melddoc.MeldDoc, gnomeglade.Component):
         self.textview[new_pane].scroll_to_mark(
             new_buf.get_insert(), 0.1, True, 0.5, 0.5)
 
+    def _set_external_action_sensitivity(self):
+        have_file = self.focus_pane is not None
+        try:
+            self.main_actiongroup.get_action("OpenExternal").set_sensitive(
+                have_file)
+        except AttributeError:
+            pass
+
     def on_textview_focus_in_event(self, view, event):
         self.focus_pane = view
         self.findbar.textview = view
         self.on_cursor_position_changed(view.get_buffer(), None, True)
         self._set_save_action_sensitivity()
         self._set_merge_action_sensitivity()
+        self._set_external_action_sensitivity()
         self.update_text_actions_sensitivity()
 
     def on_textview_focus_out_event(self, view, event):
         self._set_merge_action_sensitivity()
+        self._set_external_action_sensitivity()
 
     def _after_text_modified(self, buffer, startline, sizechange):
         if self.num_panes > 1: