QT4: Autoresizing / shapechanging layout?

First of all, I only just found this new forum and posted the same question to the old one. Anyway, it looks great! Good job!

I've created a layout that needs to change its size when the user hides a section of it. Look at the screenshot. It's pretty straight-forward. I didn't find any existing QT mechanism for this. Strange, by the way, because I got the idea from the QT Designer toolbox. However, the provided toolbox widget doesn't have the same look or functionality. So I thought I'd use pushbuttons with small +/- icons.

I can get the widgets to hide and show themselves alright, but I can't get the dialog to change shape with it. QT3 had a simple property for this, called resizeMode. All I had to do is set it to fixed and it was out of the users hands.

How can I accomplish this in QT4?

Thanks in advance!

Look at http://www.qtcentre.org/forum/showthread.php?t=473

Thanks! Next time I'll search the forum more thoroughly.