Code review comment for lp:~faenil/ubuntu-ui-toolkit/scrollbar_moreHoverFixesAndTests

This indeed resolves the two linked bugs (which I only realized existed once I paid very close attention to the different shades of gray). I evaluated the changes with respect to the necessary implications of the behavior causing the bugs - strictly speaking it's really bad to have to deal with such counter-intuitive details of mouse area behavior so I won't say that it "makes sense".