Problem solved. The reply (on a private thread) from Rykomi (Support Admin):

This works as intended and there's nothing wrong with your browser or device or something like that."

And my answer:

"After looking again at the screenshot you sent, I noticed that the font in that image seemed smaller than what I was used to; so earlier today I tried just decreasing the font size on my computer, and lo and behold, the text appeared! So it's not just resolution and screen size, but font size, which affects the display; in other words, you can make the text reappear simply by shrinking the font, without otherwise changing the display."

Rykomi's final comment:

"The font size affects the element's width, so it fits there if it's smaller indeed. :)"

I am one of those "very few people", at least on FA, which is a massive site. Rather than browse every day, which I don't really have time to do, I tend to catch up about once a month; and the only way to reduce a full month's submissions to a manageable number is to run several dedicated searches - for instance, [bovine | bull | tauren | minotaur] using the "or" function, or [(equine | horse | donkey | zebra | stallion) & solo] using both "or" and "and". This makes the site much more user-friendly for me - and I hardly consider myself a "power user"!

I can understand not putting it on the front burner if not many people want or need it, but I would hope that it would eventually be implemented. People have talked about Furry Network as an alternative to FA, but if it's ever going to grow beyond a small "boutique" site, you ought to have good ways to deal with large numbers of submissions - and lots of users, particularly new ones, who may want to look through your entire site, but only for certain things.