Hi Granddad Seaside, please ignore the spam message with an unofficial support number.

After the initial problem with the Bookmarks Toolbar not being visible, and changing the window to get it back, does the problem recur again during the same session, or not until the next Firefox startup?

Hi jscher2000 and thanks for taking the trouble getting back to me. It happens at the next Firefox start up. OK for each session once I go through the go round.

When I was searching I checked and found an extension new to me...AutoFullScreen...I disabled it and all back to normal now. Thanks again. Alan

I'm glad you found it. You should be a little ruthless with Extensions: any extensions Firefox installs for built-in features are hidden from the Add-ons page, so everything listed there is your choice (and your responsibility) to manage. You might want to check every few weeks in case other strangers are lurking.