Try a different layout manager for your jPanel1
public void createPanel1() {
jPanel1 = new JPanel();
//jPanel1.setLayout(new GridLayout(0, 1);
jPanel1.setLayout(new BoxLayout(jPanel1, BoxLayout.Y_AXIS));
jPanel1.setBorder(new TitledBorder("Select a Layout Manger"));
jPanel1.add(jrbFlowLayout);
jPanel1.add(jrbGridLayout);
jPanel1.add(jrbDiagLayout);
ButtonGroup buttonGroup1 = new ButtonGroup();
buttonGroup1.add(jrbFlowLayout);
buttonGroup1.add(jrbGridLayout);
buttonGroup1.add(jrbDiagLayout);
}
GridLayout
...
BoxLayout
...
I'd almost suggest GridBagLayout
, but that's probably overkill in this case...