[pitivi] viewer: Ensure the widget for displaying video is visible when switching output

[Jean-FranÃois Fortin Tam <jfft src gnome org>]

commit af424833aeef616763d7d8c8832fc24943dddbd6
Author: Jean-FranÃois Fortin Tam <nekohayo gmail com>
Date:   Sat Nov 17 17:39:16 2012 -0500

    viewer: Ensure the widget for displaying video is visible when switching output
    
    Making this method more fool-proof prevents some silly bugs and warnings
    that kept occuring even if the rest of the code made sense.

 pitivi/viewer.py |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/pitivi/viewer.py b/pitivi/viewer.py
index e83598a..a7de605 100644
--- a/pitivi/viewer.py
+++ b/pitivi/viewer.py
@@ -469,6 +469,8 @@ class PitiviViewer(Gtk.VBox, Loggable):
 
     def _switch_output_window(self):
         Gdk.threads_enter()
+        # Prevent cases where target has no "window_xid" (yes, it happens!):
+        self.target.show()
         self.sink.set_window_handle(self.target.window_xid)
         self.sink.expose()
         Gdk.threads_leave()