Is it possible to reset the layout's height to original one?

Hi, Sir:
I add some buttons in a dumy widget. Then, include another button (button1) and this widget into a VBoxLayout. In constructor, I hide the widget, and connect the button with widget to be able to show these buttons after pressing the button1.

Things like below
___________________
Button1 ---> Button1
.................. Button2
.................. Button3
___________________

But, after that, the height of layout cannot be back to original height.
Is there any way to reset the just-fit layout height???

Thanks a lot.

BR,
Pico

You mean something like this -- [wiki]Expanding dialog[/wiki]?

Hi, Sir:
yes... I would like to have expanding buttons...

Thanks