First thing I learned to do in Workshelf was to consign those dividers to oblivion.
Well ...... now you tell me. Okay so .... how do I consign them to never never land.
The icon dividers in the Shelf can add a really nice 3D effect, but for that to happen the skinner who made the theme must remember to set their colors properly. Some Winstep skinners (Gizmoid, *cough*cough*) don't use them and then, of course, don't set the colors and forget that the dividers actually show up by default on other people's systems.
To turn the dividers off, Uvah, right click the left Shelf mini-tab -> Appearance and Sounds -> Hide frames around the icons.