>> That's precisely what I've been investigating during the last day.  I 
>> probably need two or three more days to reach a conclusion, so please 
>> tell me if you're doing that in parallel.
>
> I'm not.  I did the measurements, and so did Gerd, but I'm not looking 
> into the font-lock influence any deeper than that.
>

Okay, thanks; I can continue without fearing that I might be wasting my 
time 😉