<div dir="ltr">Thanks for reporting. Put this after loading bidi package and before \begin{document}:<br><br>%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%<br>\makeatletter<br>\newcommand\bidiraggedleft{\if@RTL\raggedright\else\raggedleft\fi}<br>
\newcommand\bidiraggedright{\if@RTL\raggedleft\else\raggedright\fi}<br>\def\@makechapterhead#1{%<br>  \vspace*{50\p@}%<br>  {\parindent \z@ \if@RTL\bidiraggedright\else \normalfont<br>    \ifnum \c@secnumdepth &gt;\m@ne<br>
        \huge\bfseries \@chapapp\space \thechapter<br>        \par\nobreak<br>        \vskip 20\p@<br>    \fi<br>    \interlinepenalty\@M<br>    \Huge \bfseries #1\par\nobreak<br>    \vskip 40\p@<br>  }}<br>\def\@makeschapterhead#1{%<br>
  \vspace*{50\p@}%<br>  {\parindent \z@ \bidiraggedright<br>    \normalfont<br>    \interlinepenalty\@M<br>    \Huge \bfseries  #1\par\nobreak<br>    \vskip 40\p@<br>  }}<br>\makeatother<br>%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%5<br>
<br>Best Wishes,<br>Vafa Khalighi<br></div>