I don't get it, FTP simply uses two independent list boxes. They don't use each other. It's the program that reads the content from a row in one listbox and copy the data into a new row in the other listbox.

Unless you'd want them to move synchroniously... then perhaps you should rather use something like a table control: one listbox with two columns.

Hmm, there's a thought. An FTP client that shows the difference between two directories. You know those GUI diff clients, like ExamDiff and WinMerge? These show two textboxes side by side, with a colour coding of what has changed, what was added, edited, or deleted. A similar tool, comparing local directory and remote directory, that seems like a good idea. Now that I just thought it up, it does. :)

If anyone wants to run with the idea and do something with it: you have my blessing. Just don't try to patent the idea. ;-|