The docs indicate that if you return 2 in the RetrieveStart event of a DataWindow (or DataStore), a call to Retrieve() will append rows to the DW.
In fact, what it appears to do, if there is a defined sort order on the DW, is re-sort it after the Retrieve has added the rows. That does not appear to be documented, and took me a whole bunch of debugging (actually got-here messageboxing, the debugger kept crashing!) to figure out why a feature that used that was doing something entirely wrong.
Is this a documentation bug? Feature bug? (I personally think it shouldn't do that.)
Never mind Dan, it's been along week!
All the best
David