Sets the size and screen position of an appbar. The message specifies a screen edge to and the bounding rectangle for the appbar. The system may adjust the bounding rectangle so that the appbar does not interfere with the Windows taskbar or any other appbars.
SHAppBarMessage(ABM_SETPOS, pabd);
Always returns TRUE.
This message causes the system to send the ABN_POSCHANGED notification message to all appbars.