Hello, as a matter of fact there is a shortcut key (displayed in the sidebar menu since FF 60.0.1).
However Ctrl+B is already assigned to open the native bookmark sidebar and cannot be redirected.
So the following keys have been assigned from the few free left I could find:

- Linux = Ctrl+Shift+B
- MAC = Alt+B (Cmd+Alt+B doesn't match with authorized key pattern .. it is rejected)
- All others, including Windows = Ctrl+Q

Cf. https://github.com/aaFn/Bookmark-search-plus-2/issues/4