Content ctn1 = contentManager.addContent("ctn1", "ctn1", null, new JButton("ctn1"));
PropertyChangeListenerTracer ctn1Tracer = new PropertyChangeListenerTracer();
ctn1.addPropertyChangeListener(ctn1Tracer);
Content ctn2 = contentManager.addContent("ctn2", "ctn2", null, new JButton("ctn2"));
PropertyChangeListenerTracer ctn2Tracer = new PropertyChangeListenerTracer();
ctn2.addPropertyChangeListener(ctn2Tracer);
Content ctn3 = contentManager.addContent("ctn3", "ctn3", null, new JButton("ctn3"));
PropertyChangeListenerTracer ctn3Tracer = new PropertyChangeListenerTracer();