procedure TMainForm.Button1MouseDown(Sender: TObject; Button: TMouseButton;
Shift: TShiftState; X, Y: Integer);
begin
Label1.Visible := true;
end;

procedure TMainForm.Button1MouseUp(Sender: TObject; Button: TMouseButton;
Shift: TShiftState; X, Y: Integer);
begin
Label1.Visible := false;
end;