Brief outline of the issue

Check/indicate

• Relevant to the xepersian package
• The bidi package issue tracker has been searched for similar issues?
• The xepersian package issue tracker has been searched for similar issues?
• Links to <tex.stackexchange.com> discussion if appropriate
• Links to <qa.parsilatex.com> discussion if appropriate

Minimal example showing the issue

% !TEX TS-program = XeLaTeX
% !TEX encoding = UTF-8 Unicode
\documentclass{article}

\usepackage{fancyhdr}
\renewcommand\headruleskip{10cm} %<< doesn't change anything
\let\footrule\hrulefill %<< doesn't change anything
\pagestyle{fancy}
\usepackage[RTLdocument]{bidi}

\begin{document}
	Test
\end{document}

Expected behavior

The headrule should be under "Test", there should be another rule at the bottom of the page.