Unable to override default shortcut on Firefox

[FranklinYu]

The add-on description says that it cannot override the shortcuts outside of the webpage, which implies that it works within the webpage. I tried the “do nothing” for Command Shift P but Firefox still opens a private window, even when I focused on a text box on GitHub.

[benintech]

Same here. I bind ctrl+w to "do nothing", but it still closes the current tab (FF133). I even checked "Active while in inputs" and "All sites", but nothing works.