OK, I have rebuilt the site to where is should have been using the downloaded source code. The problem persisted, so I built a test site, and with a style sheet as specified above.

After applying the style sheet to the default page (in design view) no listing was shown. However, when I switched to the the default page, it was clear the styling had been applied. Switching back to Manage Styles, this listing showed for less than a second (I was quick on the print screen button!) - but then the listing disappeared.

A similar thing happens for View|CSS properties (Fig 3-16). Momentarily the properties are there - then they vanish.

Could be that VWD needs re-installation, I suppose - but unless something else crops up, I don't think I will do that. This is not the end of the world, I can manage CSS styles without the assistance of VWD - but I am puzzled as to why it is happening, and would appreciate your thoughts.