After you do a relationship type edit search, the criteria are broken. The list of relationship types is no longer shown. If you press "search" without changing anything, the relationship type criteria vanishes.

e.g.
http://beta.musicbrainz.org/search/edits?order=desc&auto_edit_filter=&negation=0&combinator=and&conditions.0.field=status&conditions.0.operator=%3D&conditions.0.args=1&conditions.1.field=link_type&conditions.1.operator=%3D&conditions.1.args=102&field=Please+choose+a+condition