OutputTabTerm instances don't appear in list of
all TopComponents obtained by this:

 Iterator it =
TopComponent.getRegistry().getOpened().iterator();
 while (it.hasNext()) {
     System.out.println("TC="+it.next());
 }

From the sources I have looked at, I suspect that
OutputTabTerm should not implement
TopComponentListener because WindowManagerImpl
registers a TopComponent by calling
topComponentOpened() itself.