Перемещение компонента PaintBox с помощью мыши

void __fastcall TForm2::FormPaint(TObject *Sender)
{
PaintBox->Canvas->Draw(ImX,ImY,jpg);
}
 
void __fastcall TForm2::FormMouseUp(TObject *Sender, TMouseButton Button,
      TShiftState Shift, int X, int Y)
{
MouseD=false;        
}
 
void __fastcall TForm2::FormMouseDown(TObject *Sender, TMouseButton Button,
      TShiftState Shift, int X, int Y)
{
MouseD=true;
Dx=X-ImX;
Dy=Y-ImY;
}
 
void __fastcall TForm2::FormMouseMove(TObject *Sender, TShiftState Shift,
      int X, int Y)
{
if(MouseD==false)return;
int ty=Y-Dy;
if(ty>0)ty=0;
if(ty+jpg->Height>=PaintBox->ClientHeight)
{
ImY=ty;
PaintBox->Canvas->Draw(ImX,ImY,jpg);
}
}

back=new Graphics::TBitmap();
back->Width=PaintBox->Width;
back->Height=PaintBox->Height;

void __fastcall TForm1::PBoxMouseMove(TObject *Sender, TShiftState Shift,
      int X, int Y)
{
if(Shift.Contains(ssRight))
     {
     ScrollH->Position-=X-LastX;
     ScrollV->Position-=Y-LastY;
     }
LastX=X;
LastY=Y;
}
//---------------------------------------------------------------------------
 
void __fastcall TForm1::ScrollHChange(TObject *Sender)
{
     PBoxY->Repaint();
    PBoxY2->Repaint();
    PBox->Repaint();
}
//---------------------------------------------------------------------------
void __fastcall TForm1::ScrollVChange(TObject *Sender)
{
     PBoxY->Repaint();
    PBoxY2->Repaint();
    PBox->Repaint();
}