see http://bugs.musicbrainz.org/ticket/4631 and MBS-201

One day we'll hopefully be able to use all advanced search syntax as requested in MBS-201, but until then it would be useful to be able to paste an MBID (or a full URL containing an MBID) instead (the original ticket was asking for it in the AJAX lookups, but it would be useful pretty much anywhere where the search is used when editing, e.g. merging recordings)