Comment 1 for bug 55555

I think 4. has to do with what the options seem to advertise. For instance:

 * Hide bugs that are open upstream
 * Show only bugs that are closed upstream

The behaviour for the third option is mysterious for bugs which have no upstream bug report linked.

(To be honest, what's the semantic difference between the third and fourth options?)

The behaviour for the fourth option seems to be just wrong. Issue the query:

https://launchpad.net/distros/ubuntu/+bugs?field.searchtext=&orderby=-importance&field.status%3Alist=Unconfirmed&field.status%3Alist=Needs+Info&field.status%3Alist=Confirmed&field.status%3Alist=In+Progress&field.status%3Alist=Fix+Committed&assignee_option=any&field.assignee=&field.owner=&field.component-empty-marker=1&field.status_upstream=only_closed&field.status_upstream-empty-marker=1&field.omit_dupes.used=&field.omit_dupes=on&field.has_patch.used=&field.has_no_package.used=&search=Search

and inspect some of the bugs in the results:

https://launchpad.net/distros/ubuntu/+source/sketch/+bug/5347
https://launchpad.net/distros/ubuntu/+source/krb4/+bug/27948
https://launchpad.net/distros/ubuntu/+source/convertfs/+bug/31401
https://launchpad.net/distros/ubuntu/+source/xorg-server/+bug/36461
https://launchpad.net/distros/ubuntu/+source/scim/+bug/42024

not one of those has an upstream bug task associated with it. So I'm not sure why they are being returned.