Man, I hate the fact I can't put TABs in these HTML text input boxes... Let's try this again. Create a callback routine that will be called when the user left-clicks in the main palette window: Pro Color_Callback, Color, pData Print, Color End Next, create a base in which the selection widget will appear TLB = Widget_Base() Create the color selection widget using OBJ_NEW with the first parameter set to the base widget's ID and the CALLBACK keyword set to the name of your routine. oColor = Obj_New('colorannotationselection', $ TLB, Callback = 'Color_Callback') You can think of the "pData" argument in the callback as the equivalent of a *pointer* to a widget's UVALUE. You specify the initial value to this via the CB_Data keyword to OBJ_NEW.