I'd like to write a document using this template : http://phd.epfl.ch/modelesthese. When i'm compiling with pdflatex, there's no problem and the chapter headers are fine.
Here is a MWE :
\documentclass[a4paper,11pt,fleqn]{book}
\usepackage{tikz}
\usepackage[explicit]{titlesec}
\begin{document}
\begin{tikzpicture}[remember picture,overlay]
\node[yshift=-8cm] at (current page.north west)
{\begin{tikzpicture}[remember picture, overlay]
\draw[fill=black] (0,0) rectangle(35.5mm,15mm);
\node[anchor=north west,yshift=-7.2cm,xshift=37mm,text width=\textwidth,minimum height=30mm,inner sep=0mm] at (current page.north west)
{\parbox[top][30mm][t]{\textwidth}{Chapter One}};
\end{tikzpicture}};
\end{tikzpicture}
\end{document}
But with xetex, there is an issue with the chapter header. The position of the text isn't good.
With pdflatex :

With xelatex :

Does anyone know why and how to fix it?

\documentclass{...}and ending with\end{document}.pdflatexandxelatex:\documentclass[a4paper,11pt,fleqn]{book}\ifx\XeTeXpdffile\undefined\else\newcount\pdftexversion\pdftexversion140\def\pgfsysdriver{pgfsys-dvipdfm.def}\fi\usepackage{tikz}\usepackage[explicit]{titlesec}\begin{document}...\end{document}