Can't write on signs

For quite a while I have not been able to see the text being typed when placing a sign nor able to apply any text to it.
It locks up until I push ESC or click, and then the sign is empty no matter if I tried typing anything.

I have tried placing it with and without using Shift-click. It makes no change, the typing area GUI does not show up.

I also tried uninstalling and installing it again from Windows Store. It makes no change...