Integrated Help prevents from assigning a shortcut to F1

Hi.
I’m trying to assign “mirror” on F1 so that I can flip my view easily. However when I try to assign this key to that function in the keyboard shortcuts window, the integrated help window pops up and prevents from rebinding the key.

I’ve tried unbinding the help/integrated help keyboard shortcut, but it doesn’t help. I’ve also relaunched the program since unbinding the shortcut and tried again, which also does nothing.

It seems like unbinding it works only back in the main workspace; if I try to press F1 in the workspace nothing happens (working as intended), but for some reason in the keyboard shortcuts window Toon Boom totally forgets I’ve unbound that button.

I’m using Toon Boom Harmony 21.0.1 (17727) Premium on Windows 10 if that makes a difference

Help

Can confirm, must be a bug report to support.