looks like in 4.2.7 fixed.
What version of WinSCP are you using?
Sometimes when press "Save" in external editor, WinSCP trying connecting to server for upload new version, but nothing happend. Looks like can't but trying and trying again. I tried close it - nothing. Close WinSCP - it still in memory. Last strings from debug log:
~~~~~~~~~~~~
------ // -----------
. 2010-03-02 16:27:16.028 Looking for network events
. 2010-03-02 16:27:16.028 Timeout waiting for network events
. 2010-03-02 16:27:16.540 Session upkeep
. 2010-03-02 16:27:16.540 Looking for network events
. 2010-03-02 16:27:16.540 Timeout waiting for network events
. 2010-03-02 16:27:17.042 Session upkeep
~~~~~~~~~~~~