What is this Windows 10 black rounded box with home and number 1 inside it?

[Windows Central Question]

Windows 10 black rounded box with home and number 1 inside it.

I've just updated to Windows 10 Pro from Windows 8.1 Pro.
There is a black rounded box with home and number 1 inside it.
This box covers a part from any other application window. It is on top of every application windows.
Anyone knows why and how to get rid of it.
Thanks!

 

[michail71]

Re: Windows 10 black rounded box with home and number 1 inside it.

I think this requires a picture.