[lucida] Lucida OT equality symbol looks faint in Adobe Acrobat

[Karl Berry]

    horizontal fat lines made of a bluish cross patterns at vertical
    positions 349 and 615 in the text font. 

Maybe they are guidelines of one kind or another? If you play around
with the Layers menu, maybe they'll (dis)appear. But why the text font
should show more guidelines than the math font, I could not guess.

Michael (or anyone), maybe you know off the top of your head from
Bruno's screenshot?

In any case, if they are just guidelines, that would just be transient
in the FontForge display, so not likely they are connected to triggering
the Acrobat rendering bug. Which, BTW, has anyone reported it to Adobe?

As for a workaround in the font, looking at dumps from ttx is all I can
think of to see what's really different and what might be changed. It
could be anything. I won't be able to do this any time soon, but I'll
add it to my list.

    whether it's connected to hinting.

In principle there should be no hints in Lucida fonts, unless FontForge
decided to add them on its own hook. B&H (intentionally) never defined
them. FWIW, my recollection is that hinting lines shown in FF are thin.

    <https://fontforge.org/docs/ui/mainviews/charview.html>, 

Good job finding that page, though I can't find an explanation either.

Best,
Karl