I believe the issue has to do with the FTP connection being unexpectedly disconnected. I occasionally get a Reconnect dialog, but most of the time, WinSCP just grays out and I have to close it down.
Just to be clear, this happens EVERY time I use WinSCP. The only reason I continue using WinSCP is that I can't find another freeware FTP program that has all the great features of WinSCP.
I can't tell you how incredibly frustrating it is to have WinSCP constantly freezing up and being forced to restart it.