[Cinnamon 1.6] Firefox does not exit Private Browsing properly when there multiple windows on multiple workspaces

[Adam Bruce]

Linux Mint 13 Maya + Cinnamon 1.6 (64bit)

Reproduce:

- Create 2 workspaces
- On workspace 1, launch one firefox window.
- On this firefox window, open 2 tabs.
- Go to workspace 2, launch another firefox window.
- On this firefox window, open 2 tabs.
- In this firefox window, go to Tools>Start Private Browsing
- Go to Tools>Stop Private Browsing

- The firefox window from workspace 1 will now appear on workspace 2 and will not function properly. It appears to be a maximized window, but only the size of a quarter of the screen.

Please note that this does not seem to happen with only 1 tab in each firefox window