In WinSCP item of queue is a complete batch transfers. Some other clients (e.g. FileZilla) have a single file as item. WinSCP may optionally support this mode as well.
For beginning we can queue each selected item individually only. So if directory is selected, it would be one item in queue (not one item for each file in directory). This should be quite easy to implement.
Only individual enqueuing of selected items (non-recursive) is implemented.