TopComponentGroup semantics

I've been struggling with TopComponentGroup semantics. Basically, I have a TopComponent class A, and a singleton TopComponent B that displays property sheets relating to A. So, in my window system delcarations, I make a group containing the singleton B.

The trick is, when do I call open() and close() on the TopComponentGroup? The conventional wisdom is to have:

protected void componentActivated() {
 super.componentActivated();
 TopComponentGroup group = WindowManager.getDefault().findTopComponentGroup(TC_GROUP);
 if (group != null) {
  group.open();
 }
}

protected void componentDeactivated() {
 TopComponentGroup group = WindowManager.getDefault().findTopComponentGroup(TC_GROUP);
 if (group != null) {
  group.close();
 }
}

This, however, doesn't work. For one thing, when I click on B, I am deactivating A. Therefore, clicking on B makes it disappear! My next thought was to use componentShowing() and componentHidden() instead of activated/deactivated. But, if I have 2 A's showing in different modes, that paradigm breaks down. Long story short(er), this is what I ended up with, and it seems to work:

protected void componentActivated() {
 super.componentActivated();

 TopComponentGroup group = WindowManager.getDefault().findTopComponentGroup(TC_GROUP);
 if (group != null) {
  group.open();
 }
}

protected void componentHidden() {
 Mode m = WindowManager.getDefault().findMode(this);
 if (m == null) {
  // if the component is hiding because it is being closed,
  // we must back off to assuming the editor mode
  m = WindowManager.getDefault().findMode(EDITOR_MODE);
 }

 TopComponent selected = m.getSelectedTopComponent();
 if (selected == null || !(selected instanceof PageEditor)) {
  // close the TC_GROUP
  TopComponentGroup group = WindowManager.getDefault().findTopComponentGroup(TC_GROUP);
  if (group != null)
   group.close();
 }
}