Description of problem:
I'm seeing backtraces that start with the above error on Fedora 15. I'm using a fairly complex piece of software -- http://www.anvil-software.de/ -- and the error occurs when closing a modal dialogue box while trying to save.

This seems to be a bug that was recently fixed in Debian (I'll add the link shortly), with a fairly simple fix.


Version-Release number of selected component (if applicable):
java-1.6.0-openjdk-1.6.0.0-59.1.10.3.fc15.x86_64

How reproducible:
Every time

Steps to Reproduce:
1. Try to save from Anvil
  
Actual results:
Exception occurred during event dispatching:
java.lang.NullPointerException
        at sun.awt.X11.XWindowPeer.restoreTransientFor(XWindowPeer.java:1681)
        at sun.awt.X11.XWindowPeer.removeFromTransientFors(XWindowPeer.java:1747)
        at sun.awt.X11.XWindowPeer.setModalBlocked(XWindowPeer.java:1469)
        at sun.awt.X11.XWindowPeer.setModalBlocked(XWindowPeer.java:1440)
        at java.awt.Window.setModalBlocked(Window.java:1359)
        at java.awt.Dialog.unblockWindow(Dialog.java:1597)
[ ... etc ...]