If the Solidworks shell extension keeps causing the mouse cursor to change (which is interesting; maybe it is launching a helper process each time an icon is requested?), that could explain the tie-in with CursorFX. Maybe Solidworks is putting the machine under a lot of load to generate the icons and that's making CursorFX slow to load its cursor resources, which then blocks the UI thread. Just a theory, though.
Of the columns you mention, Folders (Total) and Files (Total) both cause the entire subdirectory of each displayed folder to be read, recursively, so they could be causing additional disk access in the background which may have some effect, either positive (the directory listings will be cached, if something else then requests them) or negative (the extra disk access could slow something down that's also using the disk). (If the subfolders only have a few files, or there are no subfolders, then I would not expect those columns to have much effect at all, on the other hand.)
AV may well be involved, as in any performance issue.
How to find components causing high CPU usage may be worth a try.