Mouse Not Disappearing.

When I press escape, then go to a youtube tutorial, then go back to Minecraft, then press escape again, the mouse appears. It can be fixed by pausing, then un-pausing again, but it is just annoying. See video for more info.

This also affects 1.12.2, I just couldn't get it to say "1.12.2"

 

Video:

https://www.youtube.com/watch?v=-RPZ1Gd0NRw