Q:

Unusuable windows pops up using Shift + 2 in Ubuntu 18

So.. when I try to do Shift+2, I get the pop-up shown in the image. Happens using keyboard config of English (US), but not when using English (UK), then I get a "-symbol as expected. However, when performing the combination to produce a @-symbol, I get the same 'pop-up'-screen as with the English (US) config.
Anyone knows why this happens and what it is?

EDIT:
Using gnome-control-center keyboard to find the keymapping for the Shift + 2 combination.. I find that it maps to

Removing that mapping will change it to Shift+Super+Home, which allows me to use Shift+2 to display @ once again.

A:

You should check the keyboard shortcuts in GNOME Control Center (Keyboard tab):

Open it from dash (or with gnome-control-center keyboard)
Compare your settings with default settings below:

and locate or change the problematic items.

