Noticed that if I am rapidly scrolling using my touchpad on certain pages in the upper right side of the pages (easiest way for me to reproduce, but may occur elsewhere) causes the tab bar to move left (as in, eventually, the first tab in the window will be shown).
The tab bar moves
Tab bar does not move.
17:30.66 INFO: No more inbound revisions, bisection finished.
17:30.66 INFO: Last good revision: b8f19d6b876273bc08c8e82bf72282d923a97a7d
17:30.66 INFO: First bad revision: f7bd517e7949ca3bbc000f704087daba4bc5ccfb
17:30.66 INFO: Pushlog:
Too late for a fix in 70 but we could still take a patch for 72.