Found a couple of issues. Tested on MacOS.
Reset Category does not work in VideoDirector tab.
“+” Button does not work in Global Layer, Global Stack, Module and GlobalModule unless a Global Part has been added. But then they are available in any Project regardless of whether there is a Global Part or not.
Unable to clear any single assignment in MacOS as backspace is seen as a valid shortcut key. Have to assign a key already used (e.g. space for Transport start/stop) and then set the original key again or load previously saved settings. Perhaps a reset button for single items would be appropriate.
It would be handy to be able to load a category from a full actions file (i.e. open file, select category).