Description Andy Doddington 2005-01-21 04:37:23 EST

I have a requirement to notify a View when the selection changes in any instance
of a particualr editor. The editor contains a jface Viewer which is the natural
selection provider.

I register each editor's viewer with the site, using code of the form:

    getSite().setSelectionProvider(myViewer);

I make this call in my editor's "createPartControl()" method (i.e. when the
viewer is created); I have tried writing a proxy that allows this registration
to be done in the "init()" method - but with no change to the symptoms described
below.

In my View, I have registered a listener to handle events from my editor(s), thus:

    getSite().getPage().addSelectionListener(mySelectionListener);

The issue I have is that if I specify a typeId as the first parameter for the
"addSelectionListener()" method, then I *only* seem to get events for the most
recently created editor instance. However, if I do not give a typeId then I get
events for all instances (which is what I want).

This would be fine, since I can always filter on the class of the IWorkbenchPart
that gets passed into my handler. However, this does not work for the null case
(which I also need to process). In this case I can't test the part because it is
null (natch!). However in the case of the null handler the registration process
seems to work correctly when I give the optional typeId in the call to
"addSelectionListener()" - though only for null events.

My workaround is to register two handlers - one with no typeId specified to
process 'normal' events (doing hand-written filtering), and a special null
handler which is registered using a typeId and which *only* processes null events.

Note: my original handler implemented the INullHandler interface, since I wanted
it to process both normal and null events.