Maybe this is correct because if you could sort by a column then dragging a row would be pointless. Its frustrating though because the old method of using reordercontroller behaviour seems to be deprecated? This allowed the sorting on a separate page allowing the columns to be sorted in the usual way. Have I understood this correctly?
This is on our radar and we are planning to add a dual-mode to structures in v3 onwards.
It allows the user to toggle between sorted mode and structure mode. When sorted, the dragging/reordering is completely disabled and the user can toggle between these preferences.
From v3.2 onwards, structures are now sortable by clicking the column headers. It enables pagination and search. Clicking the header a third time will restore the structure.