Touch Bar Media Play/Pause button controls Safari, not iTunes I often want to pause my iTunes music when watching a video in Safari. Currently on some sites (but not all) the Pause button starts controlling the video in Safari in stead of iTunes. 

How to permanently link the buttons to iTunes?
BeardedSpice, solved this for me. It was intended to allow the media keys to control services in Chrome, but it also can lock the media keys to iTunes.