[panel] F10 menu misplaced in multimonitor environment

[Lohith D Shivamurthy]

Steps:
1) Have dual screens
2) Let the second monitor have thunderbird (Just an example) in full screen
3) Hit(mouse click) anywhere on the second monitor
4) Hit F10
5) Main menu displayed
6) Bring the mouse cursor back to first monitor
7) Hit F10

Expected:
The Main menu belonging to the application in the first monitor is displayed.

Actual
The Main menu of the Thunderbird (example) is displayed in the first monitor.
Also the menu takes random position anywhere on the screen.
This happens whenever you move the cursor from one-screen to another screen and Open the menu by hitting F10