[news.eclipse.platform.rcp] how can a change to a viewer's content be pi

[pete@xxxxxxxxx (Pete WIlliams)]

I have two views, A and B. B shows detail of an item selected in a tree 
displayed in A. This is done via the selection service, as described in 
Eclipse Workbench: Using the Selection Service 
(http://www.eclipse.org/articles/Article-WorkbenchSelections/article.html)

So, A registers as a provider using...
getSite().setSelectionProvider(treeviewer);

And B listens using...
getSite().getWorkbenchWindow().getSelectionService().addPostSelectionListener(listener);

This works fine until the content of the tree displayed in A is updated, 
resulting 
in a selected item no longer being selected. If A is the currently 
selected part, the deselection is propigated via the selection service, 
and B can update accordingly, which is what I would expect. However, if A 
is not the currently selected part, the deselection is not propigated, and 
B is displaying detail that is no longer valid.

Does anybody know of a way of ensuring that this deselection is always 
propigated?

Thanks, Pete