I've developed one authority control to dc.contributor.author field. I've configured to open one lookup popup window in the submission page. The first time that the user call the lookup search the method getMatches is executed with all the parameters correct to my code.But, when the user ask to see more results (one button in the lookup window) the method getMatches receive the query parameter null. Using jspui interface, it works as expected and everything is ok. I've tested in both versions (1.8.0 and 1.7.2) and error is the same in xmlui interface. I've tested in the demo site (http://demo.dspace.org/xmlui) and there, one error is presented when I request to see more results in the same popup window.