Look at the code:

BEGIN_EVENTSINK_MAP (CControlWnd CDockablePane)
//}} AFX_EVENTSINK_MAP
ON_EVENT (CControlWnd, IDC_ILEDARROWX_UP, 2, CControlWnd: : OnClickIledArrowxUp, VTS_NONE)
ON_EVENT (CControlWnd, IDC_ILEDARROWX_DOWN, 2, CControlWnd: : OnClickIledArrowxDown, VTS_NONE)
ON_EVENT (CControlWnd, IDC_ILEDARROWX_LEFT, 2, CControlWnd: : OnClickIledArrowxLeft, VTS_NONE)
ON_EVENT (CControlWnd, IDC_ILEDARROWX_RIGHT, 2, CControlWnd: : OnClickIledArrowxRight, VTS_NONE)
END_EVENTSINK_MAP ()

Code in the click event is effective, but also capture in their own window class LbuttonDown,

Looking for a long time, seemed to ON_EVENT interpretation of the very few, also like a little bit on the MSDN parameter is introduced, with an example of a MouseDown, but doesn't work,
Request some Pointers so want to come to the great god, tell me what I should to direction finding information,

Like what's the meaning of the third parameter, control of event scheduling ID, do not understand, what is the third parameter values? Where can find,

HELP!!!!!!