To reproduce: - Open the Breeze theme. - Hover the ScrollBar with the mouse - the background is changed and never restored.
A fix will be introduced in the upcoming Service Pack. Give it a try and if you still experience difficulties, please consult with our support staff via support ticket.
The theme I'm working on in Visual Style Builder was pulled from Breeze, so I also have this problem in my new theme. I would like the style to stay consistent without any hover state at all.