Перемещение объектов на форме мышкой

//---------------------------------------------------------------------------
 
#include <vcl.h>
#pragma hdrstop
 
#include "Unit1.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;
//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
    : TForm(Owner)
{
}
//---------------------------------------------------------------------------
int OldX;
int OldY;
bool IsMouseDown=false;
void __fastcall TForm1::Shape1MouseDown(TObject *Sender,
      TMouseButton Button, TShiftState Shift, int X, int Y)
{
    OldX=X;
        OldY=Y;
        IsMouseDown=true;
}
//---------------------------------------------------------------------------
 
void __fastcall TForm1::Shape1MouseMove(TObject *Sender, TShiftState Shift,
      int X, int Y)
{
    if(IsMouseDown)
        {
            Shape1->Left+=X-OldX;
                Shape1->Top+=Y-OldY;
        }
}
//---------------------------------------------------------------------------
void __fastcall TForm1::Shape1MouseUp(TObject *Sender, TMouseButton Button,
      TShiftState Shift, int X, int Y)
{
    IsMouseDown=false;
}
//---------------------------------------------------------------------------

Shape1MouseDown(TObject *Sender,
      TMouseButton Button, TShiftState Shift, int X, int Y)
{
const int SC_DRAGMOVE=61458;
 
ReleaseCapture();
((TControl *)Sender)->Perform(WM_SYSCOMMAND,SC_DRAGMOVE,0);
}