Hi there. I have an NSTableView that's bound to an NSArrayController. Everything gets loaded into the table correctly, and I have sort keys and selectors set for the various columns (this also works). What I'm trying to do is sort multiple columns when the user clicks one column header, but I can't find any way to do this. I could brute-force a way by overriding tableView:mouseDownInHeaderOfTableColumn:, but that seems an inelegant way of doing it. Is there a good way of doing multi-column sorting in an NSTableView using bindings?