In theory, Dorico ought to be clever enough to work out whether the saved geometry is compatible with the current display geometry, and move the window if not. I’m sorry that doesn’t seem to be happening for you.
You can delete the file DocumentWindowPositions.ini in %APPDATA%\Steinberg\Dorico 4 to clear this cache.
As for the Manual Staff Visibility dialog not showing properly, we have had a few reports of this kind of problem, but as yet we do not have a solution. See this earlier thread: