So the general case is 'no open bugs' really means 'no bugs that you can see in this context matching your search parameters' which is very hard to special case :(.
I think something that showed the search criteria in place - using facet style search - would address this nicely.
searching in <launchpad> for bugs that are <open> <resolved upstream> ...
and you could remove a facet / add new facets. There are a lot of things related to this, but this isn't a dupe, so I'm just going to tag it up and move on :)