The "Accessibility API Permission" dialogue is a "pop over" window. It really needs a dismiss button. I can't always deal with this whenever it occurs (and it occurs too often).
I get that it's an issue with MacOS, and I get that Better Touch Tool needs these perrmissions, but there is no excuse for popping over other content for the remainder of the session.
If a limited number of features will still work, let me dismiss the message. If no features will work, add a button to simply quit Better Touch Tool for the remainder of the session.