TWMNCCalcSize = packed record
  Msg: Cardinal;
  CalcValidRects: BOOL;
  CalcSize_Params: PNCCalcSizeParams;
  Result: Longint;
end;

struct TWMNCCalcSize {
  unsigned Msg;
  BOOL CalcValidRects;
  PNCCalcSizeParams CalcSize_Params;
  Longint Result;
};