Re: New package `outline-occur'

 > Maybe we could simply allow an application to *append*
 > new rules to the end of 'display-buffer-alist',
 > thus not overriding the user customization?

Sounds dangerous. What would happen when a user customizes
'display-buffer-alist' while it's let-bound?  Note that I'm not against
the "app-action" idea and I think that appending it to
'display-buffer-alist' won't reduce the overhead it introduces.  But we
have to splice it in correctly into the list of actions we construct and
we have to be able to document it well.

martin