create a file named test.tmp.
open winscp and connect to a server using sftp.
copy test.tmp to the server, but specify an exclude mask of *.tmp.
attempt to delete test.tmp, either in winscp or in windows explorer while winscp is still running.
i noticed this because i have winscp set to exclude vim's swap files, *.swp. sometimes swap files would be left behind after closing vim and could not be deleted in windows explorer.
this occurs in both winscp 4.0 beta and winscp 3.8.2. the protocol is sftp-3. i am using the norton interface.