The EM_SETEVENTMASK message sets the event mask for a rich edit control. The event mask specifies which notification messages the control sends to its parent window.
EM_SETEVENTMASK
wParam = 0;
lParam = (LPARAM) (DWORD) dwMask;
Parameters
dwMask
New event mask for the rich edit control.
Return Values
Returns the previous event mask.
Remarks
The default event mask (before any is set) is ENM_NONE.