I am using the fixme package. I observed the use of \fxerror* or \fxnote* inside displaymath yields errors.
I can write
\documentclass[draft]{article}
\usepackage{fixme}
\fxsetup{theme=colorsig}
\begin{document}
\fxerror*{$\forall y \exists x \varphi(x,y)$}
{
\[
\forall y \exists x \varphi(x,z)
\]
}
\end{document}
with the expected result. But I sometimes would like to do something like
\documentclass[draft]{article}
\usepackage{fixme}
\fxsetup{theme=colorsig}
\begin{document}
\[
\forall y \exists x \varphi(x,\fxerror*{y}{z})
\]
\end{document}
which doesn't work. Is it a (non)feature of the fixme package?
Second point, I would like it to work with the align environnement as well as with all the other math environnement provided in amsmath.

\marginparuse not permitted in math mode. – Steven B. Segletes Aug 14 '13 at 14:56