bug#38181: Actual height of mode-line not taken into account

[Eli Zaretskii]

On May 6, 2020 9:50:06 AM GMT+03:00, martin rudalics <rudalics@gmx.at> wrote:
>  > Why do we need to enter init_iterator when the border face changes?
>  > And why do we need init_iterator to handle the face change?
> 
> If our only tool is a hammer ... Or should we call 'clear-face-cache'
> or
> 'redraw-display' whenever changing the border face?
> 
> martin

I simply don't yet understand why updating the frame decorations that have 
nothing to do with text layout needs init_iterator to run.  What am I missing?  
Redisplay doesn't in general redraw the whole frame, it only redraws windows.