Mac: Bookmark bar tooltip appears while in fullscreen mode while BMB is not visible

Repro steps:
  1. Have bookmark bar visible and fill it with enough items such that even if it took 100% screen space it would be full of items
  2. Go to twitch.tv and open a stream and make it fullscreen (from the stream UI)
  3. Go to top of screen with mouse cursor to make menu bar appear
  4. Adjust volume from menu bar control and leave mouse over the volume icon

Observed result:
  - The tooltip for some bookmark shows up (corresponding to the bookmark that would be shown at that horizontal location if the bookmark bar was visible and the mouse was over it

Expected result:
  - No tooltip appears