Thank you, my good lady! It’s a relief to know I haven’t lost my mind!
Well, I HAVE lost my mind, but anyways…
I played a bit more. It seems that if I raise the upper border of the reply windows all the way to the top, the scroll bar reappears, as long as it raises the reply to where it’s all showing.
Weird. I guess this is why I never pursued computer technology as a field. Those of you who did have my deepest respect. And empathy.