[pitivi: 12/20] timeline.py: don't move clips on mode change if we haven't already made an edit

[Edward Hervey <edwardrv src gnome org>]

commit 502d339d40874a996a323e22ca62890d23260032
Author: Brandon Lewis <brandon_lewis berkeley edu>
Date:   Tue Jul 14 18:10:40 2009 -0700

    timeline.py: don't move clips on mode change if we haven't already made an edit

 pitivi/timeline/timeline.py |   17 +++++++++--------
 1 files changed, 9 insertions(+), 8 deletions(-)
---
diff --git a/pitivi/timeline/timeline.py b/pitivi/timeline/timeline.py
index edc1e08..0586da7 100644
--- a/pitivi/timeline/timeline.py
+++ b/pitivi/timeline/timeline.py
@@ -931,8 +931,8 @@ class EditingContext(object):
         self.timeline = timeline
         self._snap = True
         self._mode = self.DEFAULT
-        self._last_position = 0
-        self._last_priority = 0
+        self._last_position = None
+        self._last_priority = None
 
         self.timeline.disableUpdates()
 
@@ -990,12 +990,13 @@ class EditingContext(object):
             self._finishRipple()
 
     def _beginMode(self, mode):
-        if mode == self.DEFAULT:
-            self._defaultTo(self._last_position, self._last_priority)
-        elif mode == self.ROLL:
-            self._rollTo(self._last_position, self._last_priority)
-        elif mode == self.RIPPLE:
-            self._rippleTo(self._last_position, self._last_priority)
+        if self._last_position:
+            if mode == self.DEFAULT:
+                self._defaultTo(self._last_position, self._last_priority)
+            elif mode == self.ROLL:
+                self._rollTo(self._last_position, self._last_priority)
+            elif mode == self.RIPPLE:
+                self._rippleTo(self._last_position, self._last_priority)
 
     def _finishRoll(self):
         pass