Registers or unregisters an autohide appbar for a given edge of the screen. This message extends ABM_SETAUTOHIDEBAR by enabling you to specify a particular monitor, for use in multiple monitor situations.
A pointer to an APPBARDATA structure. Set the lParam member is to TRUE to register the appbar or FALSE to unregister it. You must specify the cbSize, hWnd, uEdge, rc, and lParam members when sending this message; all other members are ignored.
Returns TRUE if successful, or FALSE if an error occurs or if an autohide appbar is already registered for the given edge on the given monitor.
The system allows only one autohide appbar for each edge of each monitor. The monitor is determined by the rc member and the edge is determined by the uEdge member of the APPBARDATA structure.