Quite often the document switcher dialog (opened by holding CTRL and pressing TAB) will get stuck. It does not close when releasing CTRL and its contents become completely gray. The elements in the window are still strangely clickable while in this state. The window itself seems like it has become an orphan of some sort. Switching docs again will show contents, but that looks like a second new switcher window overlayed over the old stuck one.

The following video demonstrates the problem:
http://www.youtube.com/watch?v=LSsjf_w2YG8

I am generally able to reproduce it by opening some Java source files and then start to switch between them using CTRL+TAB. It may take a while before the bug triggers, and the likelyhood of the bug occuring may be related to number of open Java source files. The dialog seems to get slower when many files are open.

The only way to rectify the problem is restarting the IDE. Happens both with Netbeans 7.2 and 7.3beta, and both with JDK6u37 and JDK7u9. Also happens on two different computers. I'm on Ubuntu 12.04 x86-64 with the standard Unity interface.

It looks like a thread is spinning when problem occurs (netbeans proc uses over 100% CPU). I did a couple of thread dumps, and this one is suspect:

"AWT-EventQueue-1" prio=10 tid=0x00007f407c082000 nid=0x485e runnable [0x00007f40cd8d9000]
   java.lang.Thread.State: RUNNABLE
	at java.security.AccessController.getStackAccessControlContext(Native Method)
	at java.security.AccessController.getContext(AccessController.java:496)
	at java.awt.AWTEvent.<init>(AWTEvent.java:106)
	at java.awt.event.InvocationEvent.<init>(InvocationEvent.java:224)
	at java.awt.event.InvocationEvent.<init>(InvocationEvent.java:188)
	at java.awt.event.InvocationEvent.<init>(InvocationEvent.java:150)
	at java.awt.EventQueue.invokeLater(EventQueue.java:1208)
	at javax.swing.SwingUtilities.invokeLater(SwingUtilities.java:1290)
	at org.netbeans.core.windows.view.ui.popupswitcher.PopupSwitcher.updateDescription(PopupSwitcher.java:155)
	at org.netbeans.core.windows.view.ui.popupswitcher.PopupSwitcher.access$000(PopupSwitcher.java:61)
	at org.netbeans.core.windows.view.ui.popupswitcher.PopupSwitcher$3.run(PopupSwitcher.java:158)
	at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:251)
	at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:721)
	at java.awt.EventQueue.access$200(EventQueue.java:103)
	at java.awt.EventQueue$3.run(EventQueue.java:682)
	at java.awt.EventQueue$3.run(EventQueue.java:680)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
	at java.awt.EventQueue.dispatchEvent(EventQueue.java:691)
	at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:158)
	at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:244)
	at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:163)
	at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:151)
	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:147)
	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:139)
	at java.awt.EventDispatchThread.run(EventDispatchThread.java:97)