I call GetFileName() in the OnFileNameOK, OnFileNameChange, and OnFolderChange overrides. I added a call in 'OnFolderChange' because the user could have had some selected files when they hit the 'Up' button to go up a directory. In this case the selection changes (clears out, actually), so I just wanted to make sure my code processed it. It does seem, however, that when the folder changes, I get an OnFolderChange callback as well as an OnFileNameChange. So it's possible I don't need to override OnFolderChange at all. OnFileNameOK isn't called at all during this process (only when I double-click a file), so at the very least, I need to put the processing in OnFileNameChange.

But regardless, the question remains the same, as in my scenario, the folder doesn't have to change to demonstrate the issue I'm trying to resolve.