+nasko in case it's related to navigation.

The original finder had another version (https://twitter.com/herrcore/status/706908497481437184) using Flash; not sure if this is the same root cause.

(Note: This bug is unrestricted because it's already been reported publicly.)

Oh man, this fell off my radar.

I investigated. It is Mac-only. On Linux, window.open kicks you out of fullscreen mode.

On Mac, it goes into fullscreen, then creates a new tab and switches to the new tab, but remains in a weird fullscreen mode. You don't see the fullscreen bubble. You can't press Esc to exit. You can only exit by using the View -> Exit Fullscreen menu.

Also tried a few variants. This one does *not* work (it kicks you out of fullscreen):

  element.webkitRequestFullScreen();
  setTimeout(() => window.open("https://test.nope/evil.html"), 0);

So it is just a weird edge case where you create and switch to a new tab while in the same event loop that entered fullscreen mode. I had a brief look at the code (chiefly browser_window_controller.mm) but I really am not familiar with how either fullscreen or window.open work on Mac. So assigning to spqchan who has worked on fullscreen stuff on Mac.

Sorry I haven't responded to this in a while. I fixed this in another bug sometime ago (involving Flash). 

There was a race condition with the fullscreen UI which puts the browser in an unusual fullscreen state. The browser will now kick you out of fullscreen. Feel free to reopen if there are still any issues

This bug has been closed for more than 14 weeks. Removing security view restrictions.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot