Perhaps it is obvious, but I have not found a method of deleting themes (removing the folder does not appear to remve them from the theme list.) Could someone please tell me how to do so...? My list is getting horribly cluttered.

Corp

after deleting the folders hit refresh list button on your popup. Or you could remove them from the themeselect.rc

Delete the theme's folder from the theme directory and refresh list.

thanks ;D