Eli Zaretskii <eliz@gnu.org> writes:
>> > The only thing I see here that's wrong is that the frame background
>> > does not hide what's beneath it.
>> 
>> In fact, if I start scrolling the buffer, I start seeing text ghosts,
>> where character cells are not being cleared, as they should be.
>
> Can you show a screenshot of that?

Here it goes -- I was scrolling downwards into the file, so the text
was moving upwards -- and you can see the undisturbed top, while the
bottom is full of stale character cells: