@Urtrek There is a new highlight setting I just got it when opera updated. IDK what they did to the UI and browser overall but it looks terrible now. I turned off the setting and the whole browser just changed on me. I think it did an update, can I undo this update? I hate it.

As to turning off the highlighting, go to settings and search TAB, it should be down near the bottom. There is an option that says Show traces on most recently used tabs then you can choose how many. Just turn this crap off.