Does not always delete the .proxy.part files when the .proxy.* final files have been generated
I'm not sure why/how this happens, but I found a couple of *.proxy.part files in my Videos folder on my laptop that also had corresponding fully-formed *.proxy.mkv files. This might be cases where I had killed or otherwise interrupted Pitivi while it was generating proxies.
Ideally, it should be able to detect the partial files, and when a complete proxy file exists offer to delete the .proxy.part file? (Though one must be careful to not wantonly delete anything *part or something). Maybe offering to move the files to the trash (rather than rm'ing them) is safer as a cleanup UX for users.