Diasble/Enable Menuitem in MFC

CMenu menu;
> menu.LoadMenu(IDR_MNU_THUMB);
>
> CMenu* pmnuPopup = menu.GetSubMenu(0);
>
> CWnd* pwndPopupOwner = this;
>
>
> if(...some conditions)
> {
> pmnuPopup->EnableMenuItem(ID_FILE_RESTORE,
> MF_BYCOMMAND | MF_DISABLED | MF_GRAYED);
> }
>
> pmnuPopup->TrackPopupMenu(TPM_LEFTALIGN |
> TPM_RIGHTBUTTON, point.x, point.y, pwndPopupOwner);
> }