Sort not available on indexed mail database

When a mail database is indexed and a search is performed, the user cannot sort on any of the columns, when the index is removed the sort “arrows” are available. Here is a quote from the help file: "Full-text indexing makes searching for documents faster and more accurate, and allows you to refine or expand your searches, and to sort your results."Notice the “AND TO SORT YOUR RESULTS” part, seems like it is working opposite to what is documented. Any ideas?

Subject: Answer

Found the solution: In the More tab I had to select a sortable selection in the Sort results by field. Not obvious as that field is not shown by defualt.