when there are lots of matches, the submit button is miles away from the release you want to add it to, e.g. http://test.musicbrainz.org/cdtoc/attach?toc=1+3+60990+150+20282+40957&artist=41636

I much prefer the way it works on the current server - http://classic.musicbrainz.org/cdi/searchartistrelease.html?artistid=41636&toc=1%203%2060990%20150%2020282%2040957&tracks=3&discid=FDX0Dvi2eymMkxHDvEdwvuzah9o-