Please change the UI of the filter/browser category lists so that the counts remain visible, always. Currently you either have to make the sidebar extremely wide to be able to see the counts when the (sub) catagory names are long, or you have to scroll in the box. Instead it is better to have the names cut off (scrollable) and the counts always visible.
So: basically, the left column (the names) should be scrollable, the right one should be fixed size.
See screenshots for an illustration of the issue.