When changing the Windows Theme, Windows has a bad habit of resetting the Windows Logon screen to its default image - and (unlike with wallpapers) DF never seems to sense this and change it back to its own settings. Granted, not the kind of thing that happens often, but it might be nice if DF could at least check it once a millenium or so...
If using the "Centre Window" button with a Windows Explorer window, the window is happily centred - except when that explorer window is closed the "new" position is not set as default, it reverts back to its original (pre-centred) placing. However, if I centre the window and then manually shift it by a pixel or two, that then becomes the new default. This only seems to happen with Explorer windows. (Win7 x64)
And I remember you being on the fence about fixing the Auto-Hide Taskbar when Empty bug - and it seems to have disappeared from the settings, so I presume it died from neglect as a feature?
For the logon screen image, opening the Settings window and clicking the Apply or OK button will re-check the logon image. I know it's not automated, but it's not too bad.
That's an interesting bug with the Explorer window, I wonder why that is? I'll see what I can find out.
Showing the Taskbar when it has items caused too many issues, so it was indeed scrapped.