HitTestThemeBackground

function HitTestThemeBackground(

  hTheme: HTHEME;

  hdc: HDC;

  iPartId: Integer;

  iStateId: Integer;

  dwOptions: DWORD;

  const pRect: RECT;

  hrgn: HRGN;

  ptTest: POINT;

  var pwHitTestCode: Word

):HRESULT;