UserAgent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/67.0.3396.87 Safari/537.36

Steps to reproduce the problem:
1. Launch Chromium in fullscreen kiosk mode (using --kiosk switch)
2. Hover mouse over top part of screen
3. Observe fullscreen exit UI floating in and click it

What is the expected behavior?
The fullscreen exit UI should not work in kiosk mode and in fact should not even be shown.

What went wrong?
The fullscreen exit UI appears and ends kiosk mode when interacted with.

Did this work before? Yes 67

Chrome version: 68.0.3440.75  Channel: stable
OS Version: Ubuntu 18.04.1
Flash Version: 

The fullscreen exit UI has been enabled by default in Chromium stable in version 68, bug https://bugs.chromium.org/p/chromium/issues/detail?id=829606 (which I can't access), code review https://chromium-review.googlesource.com/c/chromium/src/+/1073625.

It seems to partially defeat the point of kiosk mode, and should be either automatically disabled in kiosk mode, or at least be configurable through a command line switch or policies.

This is an upgrade blocker for us and might be for most kiosk installations.