BCGSuite for MFC
BCGCBPRODLLEXPORT UINT BCGM_GRID_HEADERCHECKBOX_CLICK

This registered windows message is sent to the grid's owner window by the default implementation of CBCGPGridCtrl::OnHeaderCheckBoxClick.

Parameters
wParamID of Grid Control that sent the message
lParama clicked column index.
Returns
non-zero if user processes this message.