It's not really a "real" issue, just not very comfortable design.
I think the style properties sidebar should be changed to regular tabs (instead of list) in narrow screens.
Currently it just leaves a lot of empty space.
I have made an adjustment here, though the styling isn't 100% as I want (minor doubled border on the bottom that is difficult to get rid of due to variable nature), but it should take up much less space in many cases.