This might be little known but an annoying default behavior of the game is to use any of the main mouse buttons for clicking bars. But I'd like to avoid using middle mouse because I must use it on other stuff that are spammed in fight and may accidentally go over an action bar and I can not bind it elsewhere because Logitech's latest software sucks and I must use its internal-memory mode that works across all software the same (and I need middle mouse button where it is bound on hardware to stay that way).
The addon I use is bartender for action bars but I doubt it changes anything, and it has no such option (in itself).