type
  TForm1 = class(TForm)
    Button1: TButton;
    procedure Button1MouseDown(Sender: TObject; Button: TMouseButton;
    Shift: TShiftState; X, Y: Integer);
    procedure Button1MouseMove(Sender: TObject; Shift: TShiftState; X,
    Y: Integer);
    procedure Button1MouseUp(Sender: TObject; Button:
    TMouseButton; Shift: TShiftState; X, Y: Integer);
  private
    {Private declarations}
  public
    {Public declarations}
    MouseDownPoint : TPoint;
    Moving : bool;
end;

var
  Form1: TForm1;

implementation

{$R *.DFM}

procedure TForm1.Button1MouseDown(Sender: TObject; Button: TMouseButton;
Shift: TShiftState; X, Y: Integer);
begin
  if ssCtrl in Shift then
  begin
    SetCapture(Button1.Handle);
    Moving := true;
    MouseDownPoint.X := x;
    MouseDownPoint.Y := Y;
  end;
end;

procedure TForm1.Button1MouseMove(Sender: TObject; Shift: TShiftState; X, Y: Integer);
begin
  if Moving then
  begin
    Button1.Left := Button1.Left - (MouseDownPoint.x - x);
    Button1.Top := Button1.Top - (MouseDownPoint.y - y);
  end;
end;

procedure TForm1.Button1MouseUp(Sender: TObject; Button:
TMouseButton; Shift: TShiftState; X, Y: Integer);
begin
  if Moving then
  begin
    ReleaseCapture;
    Moving := false;
    Button1.Left := Button1.Left - (MouseDownPoint.x - x);
    Button1.Top := Button1.Top - (MouseDownPoint.y - y);
  end;
end;