Bug 729267

Description of problem:
I'm using the stock netbeans 7. It used to work fine before a recent openjdk update.
When an action intends to close a window, the window do not close instead, and an NullPointer notification appears at the bottom right of the IDE. When possible, clicking three times on the button which should close the window actually closes it. However, the window that should close automatically, such as progress bars, do not close, and since they are modal, the IDE is unusable.


Version-Release number of selected component (if applicable):
THe problems appeared recently (last week), since the last jdk update I think:
java-1.6.0-openjdk-59.1.10.3.fc15


How reproducible:
Everytime

Steps to Reproduce:
1- Open netbeans 
2- open a projet: uses a modal progress bar which never closes
OR
1- have an already opened versionned project
2- Try to commit a file. First click actually commits but do not close the window. Second click do nothing. Third click closes the window.
  
Expected results:
opening projects should work. Windows should close as expected


Additional info:
stack:
http://statistics.netbeans.org/analytics/exception.do?id=523037
duplicates:
http://statistics.netbeans.org/analytics/detail.do?id=150039
And (maybe) an analysis from the netbeans guys:
https://netbeans.org/bugzilla/show_bug.cgi?id=163548