Trying out RC1, it seems that "Show Filenames" is the default for the screens that show headers, which is not a good choice for most of my groups (you can't tell what the subject is). It took me a while to find out how to show the full subject line in the group tabs (you set the "Display Settings" to None in the dropdown box), but that box isn't on the Search tab.
Is this a bug, or am I missing something?