Panels keep disappearing

In Bridge 10.1.1.166, usually when I leave Bridge to do anything else, the Favorites and Keyword panels have disappeared.  They are easy to retrieve, but it's a nuisance and waste of time.  There does not seem to be anything in common about the activities that bring this on.  It can be so Photoshop editing, or checking somethin online.  I am using a custom workspace and Windows 10 64 bit.