Initially hidden control in Qt Creator

You can try playing round with the Properties (look at setHidden), but it’s much easier to do it in the code.

So you’d do:

ui setup code
ui->groupBox->setHidden(true)

radio button slot
if true ui->groupBox->setHidden(false)
else if false ui->groupBox->setHidden(true)

That’s the easiest way really, I’ve never had much luck with adding properties in Designer that Qt already uses