After focusing on the layers widget (adding / deleting / adjusting layers) and then press the spacebar causes paint.net to crash without saving or prompt.
This is easily reproducible by the following steps:
Click add layer button on layer widget
Hit the Spacebar on the keyboard
Application crashes and notifies about pdncrash log and asks to restart or exit
When the application crashes it produces a crash report pdncrash.1 that says the following:
This text file was created because paint.net crashed. Please e-mail this to cr