I just use the long left click option, which works well for me, and I've found it's best to deselect the right click option, together with 'handle clicks on images' - which causes a problem when dragging a map, but that's to be expected.

I also use v0.4.1 on Pale Moon 28.4 On this it's also necessary to deselect 'handle clicks on bookmarks,' otherwise dragging bookmarks has to be done quite rapidly!

Thanks very much for a really useful extension :-)