User Interface not working correctly

Hey,

I´ve recently starting to use ArcMap 10.7.1 (on Windows 10) and experienced an issue with it´s GUI. In this case, I tried to create a legend with multiple columns, but the issue is that I am not able to do scroll down to choose this option.

Resizing the window is not a thing in ArcMap, or I am not aware of it yet.

Thank you very much in advance!