[pitivi] Fix a bug in popup menu sensitivity

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

commit 8eea90cbd1e2ffaee0dd4e46aed9a5b4e9ebabaa
Author: Paul Lange <palango gmx de>
Date:   Sun Jul 15 21:18:48 2012 +0200

    Fix a bug in popup menu sensitivity

 pitivi/timeline/timeline.py |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)
---
diff --git a/pitivi/timeline/timeline.py b/pitivi/timeline/timeline.py
index 9dee3ba..40bc058 100644
--- a/pitivi/timeline/timeline.py
+++ b/pitivi/timeline/timeline.py
@@ -619,10 +619,12 @@ class TimelineControls(gtk.VBox, Loggable):
         # all other cases
         last = None
         index = 0
+        first = True
         for child in children:
-            if type(child) == AudioLayerControl:
+            if type(child) == AudioLayerControl and first:
                 index = 0
                 last.updateMenuSensitivity(-1)
+                first = False
 
             child.updateMenuSensitivity(index)
             index += 1