hang/crash when an imported *mono* WAV file is dragged onto the timeline
I didn't collect a lot of details about this, but it seems to reproduce 100%, and the scenario is easy to create, so probably best left up to the person who is able to actually fix the bug to try it for themselves :-). Very reliably when I import a WAV file that happens to be mono, then drag that file onto the timeline, pitivi will either crash (happened a couple weeks ago when I tried it) or hang indefinitely while having grabbed mouse focus for the entire desktop (happened today when I tried again after updating to latest git master).
The workaround is of course to turn the WAV into a stereo file, then it can be added to the timeline without problem, but it would be nice if this extra step wasn't necessary.