EnableExplicit Define a Global ListCB Procedure ListCB(hWnd, Message, wParam, lParam) Select Message Case #WM_MOUSEWHEEL If (wParam>>16)/120 = 1 Debug "Nach oben" Else Debug "Nach unten" EndIf EndSelect ProcedureReturn CallWindowProc_(ListCB, hWnd, Message, wParam, lParam) EndProcedure If OpenWindow(0, 0, 0, 500, 400, "Window", #PB_Window_SystemMenu | #PB_Window_ScreenCentered) ListIconGadget(1, 0, 0, WindowWidth(0), WindowHeight(0), "Column", 400, 0) For a=1 To 25 AddGadgetItem(1, -1, "Item " + Str(a), 0, 0) Next ListCB = SetWindowLongPtr_(GadgetID(1), #GWL_WNDPROC, @ListCB()) Repeat Select WaitWindowEvent() Case #PB_Event_CloseWindow End EndSelect ForEver EndIf