QGroupBox elements geometry

[qt_gotcha]

I have a groupbox (using UI editor) with labels. The vertical borders around the labels (or spacing between labels) are too wide for my taste, but the geometry is linked to the groupbox size. I need to make the groupbox very large to make them readable. How can I put the labels closer together? I don't understand which groupbox property does that.
thanks

[qt_gotcha]

sorry, found it, vertical spcing etc