Praise to Andrei Gourianov, the creator of goScreen, the only really usable virtual desktop manager for Windows. He recently managed to send me my license key within a couple of hours.
The not-so-good precursor: On that said day, my trial version of goScreen (or rather, a very central part of it, the desktop maps) stopped working without prior warning (very unusual for shareware) – unfortunately in a very bad moment for me! There was no way to make it temporarily work again (e.g. by prolonging the trial period), so I had to wait for my license to arrive to continue using goScreen. The good outcome: Andrei was very understanding, responsive and co-operative and sent me my key within exceptionally short time. That saved my day and work, Andrei! Thanks again!
Kudos also to Attila who told me about goScreen the first time. I always missed something like this on Windows.