By skyforbes 
Reproduce on any laptop with a copilot button. Double tap the copilot button two times super quickly (as I did by accident while trying to press alt), such that the 2nd tap happens before the copilot window opens. Now, it is impossible to close the window by clicking the close button or by pressing alt-f4.
I only found out through googling that the only way to close Copilot in this state is to press the Copilot button again which re-launches it without the confused state, then press it again to close it