First of all, thanks a lot and good work to the FBackup team; I really enjoy the software. However, there is one issue I only realized lately on a new PC with two screens.
Specifically, on Windows 7, if there are two screens (used as an "extended display") screen #2 is the main display, FBackup will not open as a window at all. If started manually or by scheduler, it will show up in the task bar, but if you click on it you can't make the actual window show up. This is not as critical as it sounds, as backups will run anyway, and can be worked around by changing display mode from "extend these displays" to "duplicate these displays".
I should add that I used FBackup on the previous machine (single screen) before and attempted to copy the settings, however I suspect that attempt was not successful as the backup jobs I had configured there were not copied, so from my point of view it looks like FBackup has a problem deciding where to place the window on a 2 screen machine.