Lazarus merkwürdiges Verhalten

[ngott2]

Delphi-Quellcode:

 procedure TForm1.PowerupGenerator;
begin
  Randomize;
   n := Random(2);
  randomX := Random(Image1.Width - 20);
  randomY := Random(Image1.Height -20);
    case n of
    0:                                                  // gelbes powerup generiert
    begin
      Image1.Canvas.Pen.Color:=clYellow;
        Image1.Canvas.Brush.Color := clYellow;
      Image1.Canvas.Ellipse(randomX,randomY,randomX+10,randomY+10);
      Image1.Canvas.Pen.Color:=clBlue;
       Image1.Canvas.Brush.Color := clBlue;
      end;
      1:                                                     //lilanes powerup generiert
    begin
      Image1.Canvas.Pen.Color:=clPurple;
        Image1.Canvas.Brush.Color := clPurple;
      image1.Canvas.Ellipse(randomX,randomY,randomX+10,randomY+10);
      Image1.Canvas.Pen.Color:=clBlue;
       Image1.Canvas.Brush.Color := clBlue;
    end;
   end;
end;

und wird zwei mal aufgerufen