<AWT Dev> Code Review Request for CR 7128738 - dragged dialog freezes system on dispose

[Oleg Pekhovskiy]

Hi guys,

please review the fix for:
http://bugs.sun.com/view_bug.do?bug_id=7128738

webrev:
http://cr.openjdk.java.net/~bagiras/7128738.1

Description:

Entering 'move window' mode clicking window title bar sends 
WM_SYSCOMMAND with SC_MOVE inside WM_NCLBUTTONDOWN.
As a result additional message pump (for mouse capture) is created 
blocking the handlers' chain WM_NCLBUTTONDOWN -> WM_SYSCOMMAND.

So when JFrame.dispose() is called during this situation, deleting of 
native AwtFrame object could NOT be done because 
AwtComponent::CanBeDeleted() returns FALSE
(because of WM_NCLBUTTONDOWN & WM_SYSCOMMAND) and WM_AWT_DELETEOBJECT 
message is reposted over and over again (eating CPU time).

Thus I added ReleaseDragCapture(0) to AwtComponent::Dispose() to release 
mouse capture and finish the additional message pump
so that AwtComponent::CanBeDeleted() returns TRUE and AwtFrame object is 
deleted.

Thanks,
Oleg