Notifies an appbar that the user has selected the Cascade, Tile Horizontally, or Tile Vertically command from the taskbar’s context menu.
ABN_WINDOWARRANGE fBeginning = (BOOL) lParam;
No return value.
The system sends this notification message twice ¾ first with lParam set to TRUE and then with lParam set to FALSE. The first notification is sent before the windows are cascaded or tiled, and the second is sent after the cascade or tile operation has occurred.