Initially this bug was entered in NetBeans IssueZilla system as http://www.netbeans.org/issues/show_bug.cgi?id=97249
Keyboard stops responding in any java application with main frame and dialog after following set of steps:

1) Open application (for example SwingSet2 demo, or NetBeans)
2) Invoke some dialog (About dialog in SwingSet2 demo or for example Ctrl+F - find - in NetBeans)
3) Close dialog by Esc or OK

Keyboard is frozen now, nothing works, shortcuts, writing in editor or in text fields, nothing. I tried to debug and find out that key events are just not even coming, I added AWTEventListener(KEY_EVENT_MASK) and no events came when error occurred.

Good news is that bug can be workarounded - to make keyboard working again, some kind of "renewing" AWT hierarchy is needed. In SwingSet2 demo this means to switch L&F. Bug is then gone for good. In NetBeans it's needed to switch maximization by double clicking on document or view tab. In NetBeans the error appear again after repeating steps 2 and 3.

Sadly, this error seems to be reproducible only on some machines and I believe installing Beryl window manager is the key for the error to start occur.

My whole configuration: Linux Ubuntu 7.04 Feisty, default Human Theme, installed Beryl window manager. HW Notebook Sony Vaio VGN-SZ4XN/C, Graphics NVIDIA GeForce Go. Error is reproducible 100% on my machine even if Beryl WM is disabled on default Metacity WM is used. However I believe that Beryl installation changed something that triggers the bug.

I guess you'll have problems to reproduce the error. But I'm experienced developer so I can help you and do some dumps or logging for you if you tell me how and where into JDK code should I put them.

Maybe wild guess, but I think this error may be connected to http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6509038 and to the fact that Beryl is non reparenting WM.

And lastly, bug appears on JDK 1.6.0_02 and also JDK 1.7.0, build 1.7.0-ea-b11. On JDK 1.5.0_12 all works OK.