[pitivi/gtktimeline] timeline: Properly set transition tooltip text

[Thibault Saunier <tsaunier src gnome org>]

commit 0158897895e5601c70068e6707f0a7af41f60392
Author: Thibault Saunier <tsaunier gnome org>
Date:   Fri Jun 5 05:50:32 2015 +0200

    timeline: Properly set transition tooltip text
    
    Fixes http://phabricator.freedesktop.org/T85

 pitivi/timeline/elements.py |   13 +++++++++++--
 1 files changed, 11 insertions(+), 2 deletions(-)
---
diff --git a/pitivi/timeline/elements.py b/pitivi/timeline/elements.py
index bdc7952..108b1b5 100644
--- a/pitivi/timeline/elements.py
+++ b/pitivi/timeline/elements.py
@@ -27,6 +27,8 @@ is prefixed with a little b, example : bTimeline
 """
 import os
 
+from gettext import gettext as _
+
 from gi.repository import GES
 from gi.repository import Gtk
 from gi.repository import Gdk
@@ -860,8 +862,15 @@ class TransitionClip(Clip):
         self.handles.append(self.leftHandle)
         self.handles.append(self.rightHandle)
 
-        self.set_tooltip_markup("<span>%s</span>" %
-                                str(bClip.props.vtype.value_nick))
+        self.set_tooltip_markup("%s" % str(bClip.props.vtype.value_nick))
+
+    def do_query_tooltip(self, x, y, keyboard_mode, tooltip):
+        if self.__has_video:
+            self.set_tooltip_markup("%s" % str(self.bClip.props.vtype.value_nick))
+        else:
+            self.set_tooltip_markup(_("Audio crossfade"))
+
+        return Clip.do_query_tooltip(self, x, y, keyboard_mode, tooltip)
 
     def _childAdded(self, clip, child):
         super(TransitionClip, self)._childAdded(clip, child)