[XeTeX] Diacritics in color

[Aleksandr Andreev]

Khaled Hosny writes:

> use/build an OpenType font with proper combining
> mark positioning and apply the colors to individual glyphs à la what
> FireFox/LuaTeX and may be many other does.

What I get out of this comment and the post by Heiko Oberdiek is that
this should be possible to accomplish in XeTeX.

My next question is this: is this then an issue with XeTeX, dvipdfmx,
ICU or Ghostscript?

I am just trying to understand here the workflow whereby a TeX source
document becomes PDF in XeTeX and which component breaks the proper
positioning.

Thanks,

Aleks