bug#42406: Mouse-wheel scrolling can be flickering

[martin rudalics]

>> Why penalize people with >= 2 windows per selected frame when scrolling
>> one of them by updating all the others' mode, header, tab lines?
>
> BTW, I don't quite understand this question, tho: my patch definitely
> doesn't make things work any worse than they do now: currently, all
> the mode-lines (and relatives) are updated on all windows on all frames.
> My patch reduces this so it's only done on the selected frame (but still
> all windows of that one frame, indeed :-(  ).

Indeed I asked that before I realized (see my last mail to Eli) that the
old code did it the other way round and thus completely wrong IMO.

martin