Blank header in odd pages, toptesi class

Question

I'm using the documentclass toptesi by Claudio Beccari for writing my master thesis.
This class automatically produce a header, with chapter title on the even pages and section title on the odd pages.
My problem is that when I have to write the appendix I only have a title for the chapter and not for the section (no section needed), and so the result is an empty header. Is it a typo or is it right?
If is not right, what solution can I use to fix it? Like printing the same title (or none) on both pages. Here is an example of the code:

\documentclass[ 12pt, twoside]{toptesi}
\usepackage{lipsum}
\usepackage[toc,page]{appendix}
\begin{document}
\english
\indici
\chapter{First chapter}
\lipsum[1-13]
\begin{appendices}
\chapter{First appendix}
\lipsum[1-12]
\end{appendices}
\end{document}

Answer 1

Redefine \chaptermark in the appendices environment to set both the left and the right marks.

\documentclass[12pt,twoside]{toptesi}
\usepackage{kantlipsum}
\usepackage[toc,page]{appendix}
\begin{document}
\english
\indici
\chapter{First chapter}
\section{First section}
\kant
\begin{appendices}
\renewcommand\chaptermark[1]{%
  \markboth{\thechapter\ -- #1}{\thechapter\ -- #1}%
}

\chapter{First appendix}
\kant
\end{appendices}
\end{document}

I used kantlipsum because with English hyphenation it is better than lipsum.