An obscure testcase with the selection tool is:

1. RMB-drag to create a selection and popup a menu.
2. LMB-drag outside of the menu, to close it.
3. While still holding down the LMB, hold down the RMB and continue
   moving the mouse.
4. Let go of the LMB and continue moving the mouse.

etc.

KolourPaint should not crash or anything like that.