<AWT Dev> [9] Review Request: JDK-7159566 The choice positioned in the top of applet when clicking the choice.

[Petr Pchelko]

Hello, AWT Team.

Please review the fix for the issue:
https://bugs.openjdk.java.net/browse/JDK-7159566
The fix is available at: 
http://cr.openjdk.java.net/~pchelko/9/7159566/webrev/

The problem: when showing the choice popup we need to use a choice as an invoker to process grab correctly. That's why we have the piece of code I'm fixing. 
However, we also need to set a correct location of the popup. A 'heavy' getLocationOnScreen is used because the choice might have already been moved by the 
window manager by this point to fit the screen and it's the only public way to get the location of the popup menu.

The added test checks that there's no popup on the top of the window by clicking there. 

With best regards. Petr.