Different icon for non-explored folders (remote tree panel)

Great application. I'd like to post a suggestion for the remote directory tree panel (the panel that allows an easy browsing of remote directories). To understand the suggestion, I'll compare winscp with filezilla in 2 useful features of the remote directory tree panel:

• Show subdirectories with one simple click: When a remote folder is clicked (1 simple click) in a folder of the directory tree panel, then the subdirectories are shown, and a "+" is added to the folder (if some subdirectory exists). It's a very useful feature of winscp. Filezilla doesn't have this feature (filezilla requires double click, instead of simple click, to show subdirectories).
  
  
• Use a different folder icon for non-explored directories: When a remote directory hasn't been still explored (=clicked), it's shown with a "?" on the folder icon in the directory tree panel. Once a directory has been explored, the "?" is removed from the icon forever (well, for the rest of the session). It's a very useful feature of filezilla. Winscp doesn't have this feature. As a consecuence, in winscp's remote tree panel, there is no visual difference between a non-explored folder and a explored folder with no subdirectories (both of them have the same icon; none of the have a "+" at the left).
  

So my suggestion is to add (at remote directory tree panel) a "?" symbol (or a different color, or a different icon) to the folder icons that are still not explored. This will give visual&quick information to the user about directories that don't have any subdirectories, and about directories that could have subdirectories.

Thank you

Thanks for your post. This request is being tracked already:
Issue 493 – Mark non-explored folders in remote directory tree