Hashtable floatTable = (Hashtable)floatingGroups.clone();
for(Iterator it=floatingGroups.keySet().iterator(); it.hasNext();) {
Object key = it.next();
FloatingGroup group = (FloatingGroup)floatingGroups.get(key);
floatTable.put(key, group.clone());
}
// note, we're using a shallow copy of the listener list.
// it's okay that we share listener references, since we want the
// cloned Layout to have the same listeners.