Apparently fogbugz has their own nice stackexchange instance (I still wanted that for pharo).
And there is a nice feature request to list related bugs if you report one,
something I have been missing for a while at the google issue tracker. And
something I ran into a couple of times myself by not searching for other bugs
first.
so vote up!
http://fogbugz.stackexchange.com/questions/5318/feature-request-discourage-duplicate-cases