Each opened file by winscp create a temp. directory (like scp4154) and on exit all those directories got deleted automatically.
Notepad++ FTP_Synchronize plugin is not deleting temp. directories and temp. directory is named as email@example.com, so it keep all directory structure same on FTP and local.
Here is how Notepad++ FTP_Synchronize plugin save temp. files on local disk,
- and so on...
So we have a backup just like Notepad++ FTP_Sync which is really useful.
Only that feature, i prefer to use Notepad++ FTP_Sync
--== SOLUTION IS SIMPLE FOR WINSCP ==--
1- Don't Create Sub temp directory like scp4254 etc
2- On Exit don't remove any of temp directory.
--== That's it ==--