There were two problems:
* If you closed the Preset Dialog via escape the GUI interface would hang.  Note that this behavior was also found in ParaView and was fixed in its master branch.
* If you double clicked on a Palette it would crash the application - this was a side effect of a previous fix.  Instead of deleting the dialog when applying the palette, the fix should have been to queue up the deletion so it could occur after the dialog had finished processing its events.