Determining right click on the header control

You can add a check for the NM_RCLICK notfication in the OnNotify() function as shown below.

BOOL CMyListCtrl::OnNotify(WPARAM wParam, LPARAM lParam, LRESULT* pResult) 
{
	HD_NOTIFY	*pHDN = (HD_NOTIFY*)lParam;

	LPNMHDR pNH = (LPNMHDR) lParam; 
	// wParam is zero for Header ctrl
	if( wParam == 0 && pNH->code == NM_RCLICK )
	{
		// Right button was clicked on header
		CPoint pt(GetMessagePos());
		CHeaderCtrl* pHeader = (CHeaderCtrl*)GetDlgItem(0);
		pHeader->ScreenToClient(&pt);
		
		// Determine the column index
		int index;
		CRect rcCol;
		for( int i=0; Header_GetItemRect(pHeader->m_hWnd, i, &rcCol); i++ )
		{
			if( rcCol.PtInRect( pt ) )
			{
				index = i;
				break;
			}
		}

		// Add your right click action code 
	}
}