http://java.net/jira/browse/MACOSX_PORT-319 submitted 2011/08/24 by Alexander Petrov
2)Create modal dialog.
3)Set frame toFront.
Result: the dialog has lost focus for a while.
This bug is actually much larger in scope and quite visible to user. One can easily reproduce it by launching SwingSet2, choosing JOptionPane demo and then clicking "Show Message Dialog" button. Now, click on the "SwingSet2" window title bar and you'll see the window rapidly gaining and loosing focus. My understanding is that fixing this bug must be done on Cocoa level.