kdenlive is VERY finicky especially if using an older or newer version it can cause crashes, menus not to work, features not to work, things not to work properly.
A good example is that I could NOT get automask to work, there would be no box to control it until I did this full reset.
One caution is that your backup project files will be erased when doing this:
How to Reset kdenlive entirely
rm -rf ~/.cache/kdenlive
rm -rf ~/.config/session/kdenlive_*
rm -rf ~/.kdenlive/
rm -rf ~/.local/share/kdenlive/profiles/*
After this a lot of problems went away. You should do this if features aren't working or if changing your version of kdenlive. Eg running different appimages or changing your version.