Safari tabs have disappeared (but will show if move cursor to top screen)

I have a 16" 2019 MacBook Pro (Intel silicon) running macOS 15.3.2.

Prior to the issue described below, I had not been in the settings for Safari. All of a sudden my Safari tabs disappeared, although they will show if I move the cursor to the top of the screen (and of course the menu bar will show also at that time, which has always been the case). An image of what I am seeing is shown immediately below. This is in full-screen mode.

One other full-screen invocation of Safari, running at the same time (but in a different window) does show the tabs all the time, as noted immediately below.

I am at a loss for how to restore the upper display to look like the lower display (meaning showing the tabs all the time). I have searched with Google as well as on this community forum, and all I can find is information either related to web tabs, iPad tabs, grouping tabs, etc, but nothing like what I am experiencing.

This change occurred well after I did the latest OS update, so I do not believe it is associated with that (but I could be wrong!)

Any thoughts or ideas?

Thank you.