I think the following is a bug - it certainly is a nuisance. There are many instances when the selection of an image is changed without the users asking for anything remotely related. For example, when I left from editing preferences my display was reset to the beginning of the directory. WHY? This makes no sense whatsoever. In Version 9.1.0.338.

In the previous version I was using, I had three instances of Bridge aligned on my monitor. After not using them for a while (perhaps a day), two of them reset the catalog selection to the root. This shouldn't happen. This is probably another bug.