Keyboard Shortcut did not work for Firefox

[XtraLarge]

Hello,

I'm using KeePassHelper Password Manager 0.4.1 for Firefox 63.0 (64bit).
If I try to open "Keyboard Shortcut Settings" with an right-click on the icon. .... nothing happens.
Also the hint on the faq for using [ALT] + [Shift] + P did nothing.

A test on chrome works perfectly.

[belaviyo]

Go to the addons manager and press the "..." button to assign a shortcut for the extension.