Trolltech Qt Quarterly Issue 23 mentions that Layout spacing is now more "Mac Like".

This is true for QGroupBoxes placed direcly in a QGridLayout, but QGroupBoxes placed in nested layouts still have too much spacing.

The difference between the two methods can be seen in the following demo code:

#include <QtGUI>

QGroupBox *createRadio(){
QGroupBox *groupBox = new QGroupBox(("Radio"));
QVBoxLayout *glr = new QVBoxLayout(groupBox);
glr->addWidget(new QRadioButton("Button 1"));
glr->addWidget(new QRadioButton("Button 2"));
glr->addWidget(new QRadioButton("Button 3"));

return groupBox;

}

QGroupBox *createCheck(){
QGroupBox *groupBox1 = new QGroupBox(("Check"));
QVBoxLayout *glc = new QVBoxLayout(groupBox1);
glc->addWidget(new QCheckBox("Button 1"));
glc->addWidget(new QCheckBox("Button 2"));
glc->addWidget(new QCheckBox("Button 3"));
glc->addWidget(new QPushButton("Push"));

return groupBox1;
}

class Window : public QWidget{
public:
Window(QWidget *parent = 0);
};

class cDialog : public QDialog {
public:
cDialog(void);
};

Window::Window(QWidget *parent)
: QWidget(parent)
{
QGridLayout *grid = new QGridLayout();
grid->addWidget(createRadio(), 0, 0);
grid->addWidget(createCheck(), 0, 1);

setLayout(grid);

setWindowTitle(tr("Grid Layout Group Boxes Sample"));
}

cDialog::cDialog(void)
{
QVBoxLayout *vbl = new QVBoxLayout(this);
QHBoxLayout *hbl = new QHBoxLayout;

vbl->addLayout(hbl);

hbl->addWidget(createRadio());
hbl->addWidget(createCheck());

setWindowTitle(tr("Nested Layouts Group Boxes Sample"));
}

int main(int argc, char *argv[]){
QApplication myapp(argc, argv);

Window window;
window.show();

cDialog d;
d.show();

myapp.exec();
return 0;
}

#include "main.moc"