Created attachment 661 [details]
When calling setTitle in the display() method of a GLEventListener attached to a NEWT window, the program will raise an exception when closing the window. The window stays open, and none of the GLEventListener methods are called again.
See attached stack trace and error message triggered when the above occurs, and a test case.
Created attachment 662 [details]
I can confirm this bug; it appeared exactly as described with the exactly same stack trace. Commenting out the setTitle() called stopped it from appearing.