mfenced and separator not quite ok

[asmodai]

[firemath]

You probably didn't notice the second pink dot within the fences. Place your x' there. See
http://www.firemath.info/examples/example03/
for more details

Yes, the prime is located rather high.

[asmodai]

I had noticed the double pink dot, but was not sure yet if it was a bug or served some specific purpose. I'm alternating between reading the FAQ/examples and trying things from an intuitive UI experience. So apologies for the noise. Being a programmer myself I know that doing the hallway test is a good way to see if a piece of software works intuitively.

I see that you are using the one argument in an mrow idea from http://www.w3.org/TR/MathML2/chapter3.html#id.3.3.1.2 -- ok, that makes sense.