Steps to reproduce:
1. Do the "floating logo" tutorial. 
2. Play with several "plasma" layers, trying many seeds.
3. Proceed to step where the Colors, Levels are used to sharpen the text image.
4. Sometimes the app crashes.
5. Using Vista Home Premium. Colors, Levels never activates. 
6. Windows "Close Program" dialog appears: Choice to search MS site or just close.
7. Choice doesn't matter. GIMP disappears from screen in either case.
8. Searching MS site for solution makes no difference.
9. GIMP must be restarted. Do some more plasma "Colors, Levels" attempts.
10. Crashes again.

But: By uninstalling GIMP and deleting the user's ".gimp-2.6" directory the 
program will once again work.

Still will give occasional "Colors, Levels" crashes. Have to delete GIMP and directory to get rid of crashing.




Stack trace:
Stack trace not available. Crash completely exits the app. Nothing further shows on screen. No dialog, no info, nothing. 

Other information:
Crashes only appeared after varying the plasma filter seed. "Filters, Render, Clouds, Plasma." Also happens when changing a layer's blur or colors and then trying "Colors, Levels."