Oddities in the Open Recent file dialog
There are two problems with the behavior of the Open Recent dialog in MuseScore 2.0 and 2.0.1 (as of MuseScoreNightly-2015-05-04-2046-b25f81d).
First, MuseScore removes the names of currently open files from the list of recent files presented by the Open Recent dialog. This is contrary to the usual behavior of Windows programs, such as Microsoft Office components or programs such as Gimp 2. I'm not aware of any other program that removes open files from this list as MuseScore does. The difference in behavior can be disconcerting to experienced Windows users (when I first saw it I thought that something had gone wrong with my files).
Second, even if you accept MuseScore's current behavior, there is a problem with the contents of the recent list after File/Save As. This action creates a new copy of the file in question and closes the original, leaving only the new copy open in MuseScore. Therefore, the name of the original file (which is now closed) should appear in the Open Recent list as soon as the Save As has been executed. However, this doesn't currently happen. Instead, both the old and new file names are added to the list only after the new file is closed.
I have observed this behavior on Windows 8.1 but doubt it's version-specific.