It works on my four computers.....see attachment.....take mouse pointer to bottom of screen for taskbar to show, move away from bottom then taskbar disappears.....as stated in my post #2.
Do note have turned on Automatically hide taskbar as shown in post#2 yet taskbar is showing by moving mouse pointer as stated above.
Some app, most likely running in the taskbar triggers it, when doing something, like AV updating.
You could try closing all taskbar apps or hiding all taskbar icons temporarily, system icons included.
There can be a lot of different reasons as to why the task bar is popping up when watching a video in fullscreen. It could be an error, third party applications, windows issue, or even the browser.
For my solutions, I went as far as re-installing windows 10, reverting back to old drivers etc. Then I just switched to another browser and the task bar stopped popping up. Conclusion: in my case it was the browser.
Since the person has not tried another browser, it would simply not hurt. You can't just say it has to do with Windows, you have got to cover all possibilities until you find the solution. :)
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