The ZGN_RIGHTCLICK notification message is sent when the user has right-clicked in the ZeeGrid data area. The parent window of the ZeeGrid control receives this notification message through the WM_COMMAND message.
ZGN_RIGHTCLICK
idZeeGrid = (int) LOWORD(wParam); //identifier of the ZeeGrid control
hwndZeeGrid = (HWND) lParam; //handle to the ZeeGrid control