[BitBucket user: Francisco Venancio]
[BitBucket date: 2016-07-03.21:50:11]

I've deployed orthanc to query/retrieve from dcm4chee without a problem, but as we tried to use the same setup to query directly from modalities we noticed the OrthancExplorer always came up with empty queries. 

We changed query-retrive.js to send empty strings instead of asterisks as wildcard and it solves the problem with these modalities. Dcm4chee has no trouble when receiving empty strings as well, but I wouldn't change it without checking if other modalities that are working with asterisks don't break with empty strings.