Работа с ScrollBox+PaintBox

//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
    : TForm(Owner)
{
   List->Parent = ScrollBox1;
   List->Height = ClientHeight;
   List->Width= ClientWidth;
}
//---------------------------------------------------------------------------
void __fastcall TForm1::FormResize(TObject *Sender)
{
   List->Height = ClientHeight;
   List->Width= ClientWidth;
}
//---------------------------------------------------------------------------
void __fastcall TForm1::ListMouseDown(TObject *Sender, TMouseButton Button, TShiftState Shift,
          int X, int Y)
{
 
  x=0;
  y =0;
 
  List->Canvas->Brush->Color = TColor RGB(255,255,255);
  List->Canvas->Pen->Color = TColor RGB(220,220,220);
 
  List->Canvas->FillRect(Rect (0,0,List->Width,
                                  List->Height));
 
 
  while (y<List->Height)
  {
    List->Canvas->LineTo(List->Width,y) ;
    y+= 18;
    List->Canvas->MoveTo(0, y);
  }
 
}
//---------------------------------------------------------------------------

    Graphics::TBitmap * b = new Graphics::TBitmap();
           b->Assign(Image1->Picture->Bitmap);
    Image1->Picture = NULL;
    Image1->Canvas->Draw(0,0,b);
    delete b;

ScrollBox1->HorzScrollBar->Tracking = true;
ScrollBox1->VertScrollBar->Tracking = true;