I have installed the complete mtpro2, and the mtpro2.sty reads:
\NeedsTeXFormat{LaTeX2e}[1997/06/01]
\ProvidesPackage{mtpro2}
[2009/4/27 v2.3
MathTimePro II - added arc accents
MathTimePro II - fixed rbrace problem with straightbraces and morphedbraces options
MathTimePro II - fix bug with z = \backslash widetilde{\backslash sum_{x }}%
MathTimePro II v2 font support (PCTeX/WaS)%
MathTimePro II v2.1a Allowed alternate form of I in Math Script Fonts (MS)%
]
However, when I use the package with morphedbraces option as follows:
\documentclass{article}
\usepackage{amsmath}
\usepackage[morphedbraces]{mtpro2}
\begin{document}
[
\left{\right} \quad \Bigl{\Bigr} \quad
\left{\begin{matrix} 1 \ 2 \ 3 \ 4 \ 5 \ 6 \end{matrix} \right} \quad
\left{\frac12\right}
]
\end{document}
And if I use the straightbraces option, anomaly happens again:

How to fix this?
