BCGControlBar Pro for MFC

The BCGM_TOOLBARMENU message is sent to the main frame window when the user releases the right mouse button while the mouse cursor is in the client or non-client area of a control bar.

wParamThis parameter is not used.
lParamthe low-order word specifies the x-coordinate of the cursor. The high-order word specifies the y-coordinate of the cursor. The coordinates are the screen coordinates.
if the application processes this message, it should return zero.