Bug 707475

Description of problem:
I have a laptop and one external screen on the right. When I open Firefox using drag&drop, it behaves strange. This is what happens:

Right after login I press [windows] to open activities and move Firefox icon to the right screen, but it opens on my left screen. 

Then I move Firefox icon to the right screen for the second time (while the first instance of Firefox is still opened), it stays on the right screen when activities are on, but when I click on the window preview (to work with Firefox), it moves to the left screen again. 

So I open activities again and move the window to right and now it works as expected.

Version-Release number of selected component (if applicable):
$ rpm -q gnome-shell
gnome-shell-3.0.1-4.fc15.x86_64
$ rpm -q firefox
firefox-4.0.1-2.fc15.x86_64


How reproducible:
every-time

Steps to Reproduce:
1. open activities
2. move firefox icon to the right screen
3. move another firefox icon to the right screen
4. click to the firefox preview on the right screen
  
Actual results:
firefox window opens on the left screen for the first time
firefox window moves to the left screen after click on the second window preview

Expected results:
firefox window opens on the right screen
firefox window stays on the right screen after click on the second window preview

Additional info:
What is even more strange, I've registered this strange behavior only with Firefox window and it doesn't happen if I use swap screens. With some other apps drag&drop doesn't work sometimes, but I can't reproduce it every-time.