Rounded corner

Hello Dmitry

I was testing a pied of code to add a visual effect to some components on a form.
In this case, I was trying to get rounded corners to a panel.

I used this code :

procedure RoundCornerOf(Control: TWinControl);
  var      R: TRect;
           Rgn: HRGN;
  begin
     with Control do
     begin
       R := ClientRect;
       rgn := CreateRoundRectRgn(R.Left, R.Top, R.Right, R.Bottom, 20, 20) ;
       Perform(EM_GETRECT, 0, lParam(@r)) ;
       InflateRect(r, - 4, - 4) ;
       Perform(EM_SETRECTNP, 0, lParam(@r)) ;
       SetWindowRgn(Handle, rgn, True) ;
       Invalidate;
     end;
  end;

begin
     RoundCornerOf(Panel1);
end.

I get an error message : "unknown type : TRect".

Howewer, type TRect belongs to System Unit which is implemented.

Any idea about it ?

Thanks

Regards JB