Whenever I watch youtube videos the top bar (File, edit, view etc etc) starts flashing...at first it was only the top left corner, but sometimes it's the whole bar and it's awful and worrying...what could that be? I run a diagnostics and it came out clear...what could be causing this? Also, if I try and snap a screenshot of the flashing, it stops...
Thank you to anyone who might have ideas on this!
MacBook Pro (13-inch Mid 2012), OS X El Capitan (10.11.1)