XNAT-2877: Removed explicit set of dataType to session XSI type. This blocked discovery of the scan type from parameters on the query string.
Added tag 1.6.3-RC1 for changeset 6cf173715e7a
XNAT-2347: Problem occurred with scans that have no type specified. These are passed as NULL to the DownloadSessionsAction2 and have to be handled specially in the generated SQL query. Fix detects both populated and unpopulated (NULL) scan types and composes the query appropriately.
XNAT-2875 - minor cleanup of file upload dialog