"So how do I fix the stiff left button issue?"に関する回答Thanks for the hint, I didn't suspect the the metal plate but that was it indeed! For me, it was a right button issue though, it would hardly work... I filed the offending part with my dremel so it always sits flush or below the plastic (there's slight movement of the plate/bracket) and tightened the holding tabs. Been using the mouse all day long without issues so I'm a happy camper!