Actionbars now have a regression which does not allow them to be cleared in any useful way. The new accessibility setting adds a background to the text. Historically sending the actionbar as an empty string has allowed the actionbar text to be hidden/cleared, but the background now makes the empty string still render the box. There's not way to actually clear this background programatically.

Suggestion, do not render empty strings, or allow the clear title to work on actionbars too.