File Names in TOC and Contents tree Rather than Title
This is a weird problem that happens inconsistently.
Here is a screen shot:

Notice that, in both the data tree on the left and the TOC on the right, there are topics whose file name is displayed, rather than the topic Title.
This seems to happen without any action on my part, although I can't promise I didn't unintentionally do it.
Has anyone seen this problem? What causes it? How can I fix it?
Thanks!
Cindy
