Sometimes, when I hit a combination of keys (I have not figured out which one) a weird bar in the bottom-left of a screen appears. I cannot get rid of it in any way. The screencast: https://youtu.be/CdXVgth_sTk
The only way I have figured out of removing it is via:
What is the bar in question? How do you trigger it, how do you get rid of it, how to use it?