# Big brackets are always opening and square when using fontspec with MnSymbol

I have here a strange problem I don't get. When using the fontspec package in combination with MnSymbol package all big brackets in math mode are square and opening... when I deactivate one of the packages the problem is gone!

Here an example of the problem:

\documentclass{minimal}
\usepackage{etex}
\usepackage[ngerman]{babel}
\usepackage{mathtools,amssymb,amsmath}
\usepackage{fontspec}
\usepackage{etoolbox}
\usepackage{MnSymbol}

% the next line makes the definition of \mathdollar from MnSymbol void.
\undef\mathdollar

\begin{document}

Big brackets are messed up while normal brackets still work:
\begin{equation*}
\begin{pmatrix}
1 & 2 & 3  \\
1 & 2 & 3  \\
1 & 2 & 3
\end{pmatrix}
= \left( \sum_{i=1}^{n-1} i \right)
= \left( n \right)
= \big( naaaarf \big)
= (all fine)
\end{equation*}

\begin{equation*}
\left[ \sum_{i=1}^{n-1} i \right]
\end{equation*}

\end{document}


And here the result:

-

MnSymbol changes all the delimiter codes, but also fontspec does and later than MnSymbol, so the problem arises.
A possible solution is to load fontspec with the no-math option; another one is not using MnSymbol at all.
\usepackage[no-math]{fontspec}