code:
var
Form1: TForm1;
status:boolean; //s need to be global
xdif,ydif:integer; //need to be global
implementation
{$R *.DFM}
procedure TForm1.FormMouseMove(Sender: TObject; Shift: TShiftState; X,
Y: Integer);
begin
if status = false then exit;
form1.left := mouse.cursorpos.x -xdif;
form1.top := mouse.cursorpos.y -ydif;
end;
procedure TForm1.FormMouseDown(Sender: TObject; Button: TMouseButton;
Shift: TShiftState; X, Y: Integer);
begin
xdif := mouse.cursorpos.x - form1.left;
ydif := mouse.cursorpos.y - form1.top;
status := true;
end;
procedure TForm1.FormMouseUp(Sender: TObject; Button: TMouseButton;
Shift: TShiftState; X, Y: Integer);
begin
status := false;
end;