// unregister all active components
for ( int i=0; i<getComponentCount(); ++i ) {
Component c = getComponent(i);
if ( !(c instanceof JToggleButton) ) continue;
JToggleButton tb = (JToggleButton)c;
tb.removeActionListener(m_lstnr);
if ( m_group != null )
m_group.remove(tb);
}
// clear this container and add new components