WinSCP has been updated over the weekend to version 5.1.2. The new revision focuses on squashing bugs and does not introduce any new features.
One of the nagging problems solved by the developer is the one with the progress window that would pop up when the application was minimized. On the same note, WinSCP should no longer fail to reconnect the main session when files are being transferred in the background.
Also, the program would fail to report usage statistics and to close when checking for new updates. None of these issues should bother users anymore as they have been eliminated in this version.
In previous versions of the application, the system tray icon would display a tooltip on mouse hover offering details about the session and opened directory. This functionality has been restored. The entire list of fixes is available here.