The Dye Preview panel allows you to check what an object would look like before the dye is actually applied. Double clicking on a Vial of Dye and clicking on the object you wish to have dyed will bring up the panel. The panel has 4 slots for dye vials, applying however many vials you drag into the slots simultaneously once you confirm your decision. The panel will appear for armor pieces and weapons, but not for inventory containers such as bags; these will use the dye immediately. You can rotate and zoom the picture by clicking into it and then use drag and mouse wheel.