Fancyhdr - Get only section name in header of custom pagestyle

Question

So many questions around dealing with fancyhdr, but none works for me...

I have an article where I want my document title and ONLY THE SECTION NAME in the header, not the subsection, not the section number, nothing but the name. For this, I created a custom pagestyle (have different pagestyles in my document), see MWE below. But what ever I try, I still get the subsection in the title, even including its number. Why?

\documentclass{article}
    \newcommand{\maintitle}{MAIN TITLE}
    \newcommand{\docname}{My Document}
% tabular package
\usepackage{tabularx}
% header / footer
\usepackage{fancyhdr}
    \renewcommand{\sectionmark}[1]{\markright{#1}}
% define own pagestyle
\fancypagestyle{complete}{%
    \fancyhf{}%
    \lfoot{%
        \begin{tabularx}{\textwidth}{X X}
            \maintitle & Page~\thepage
        \end{tabularx}
    }
    \rhead{\docname~-~\rightmark}
}
% Let the madness begin...
\begin{document}
    \pagestyle{complete}
    \section{First Section}
        Blablubb ...
        \newpage
        \subsection{First Subsection}
            dumdidum ...
    \section{Second Section}
        Blablablubb ...
        \subsection{Second Subsection}
            dumdidumdidum ...
\end{document}

Answer 1

\subsection by default sets a right mark, too. If the subsection should never be in page header, you can redefine \subsectionmark to do nothing:

\renewcommand\subsectionmark[1]{}

Example:

\documentclass{article}
    \newcommand{\maintitle}{MAIN TITLE}
    \newcommand{\docname}{My Document}
% tabular package
\usepackage{tabularx}
% header / footer
\usepackage{fancyhdr}
    \renewcommand{\sectionmark}[1]{\markright{#1}}
    \renewcommand{\subsectionmark}[1]{}% <- added
% define own pagestyle
\fancypagestyle{complete}{%
    \fancyhf{}%
    \fancyfoot[L]{%
        \begin{tabularx}{\textwidth}{X X}
            \maintitle & Page~\thepage
        \end{tabularx}
    }
    \fancyhead[R]{\docname~-~\rightmark}
}
% Let the madness begin...
\begin{document}
    \pagestyle{complete}
    \section{First Section}
        Blablubb ...
        \newpage
        \subsection{First Subsection}
            dumdidum ...
    \section{Second Section}
        Blablablubb ...
        \subsection{Second Subsection}
            dumdidumdidum ...
\end{document}

Or you could use the left mark for the section title:

\renewcommand{\sectionmark}[1]{\markboth{#1}{}}% <- changed
\fancypagestyle{complete}{%
    ...
    \fancyhead[R]{\docname~-~\leftmark}% <- changed
}

Example:

\documentclass{article}
    \newcommand{\maintitle}{MAIN TITLE}
    \newcommand{\docname}{My Document}
% tabular package
\usepackage{tabularx}
% header / footer
\usepackage{fancyhdr}
    \renewcommand{\sectionmark}[1]{\markboth{#1}{}}
% define own pagestyle
\fancypagestyle{complete}{%
    \fancyhf{}%
    \fancyfoot[L]{%
        \begin{tabularx}{\textwidth}{X X}
            \maintitle & Page~\thepage
        \end{tabularx}
    }
    \fancyhead[R]{\docname~-~\leftmark}
}
% Let the madness begin...
\begin{document}
    \pagestyle{complete}
    \section{First Section}
        Blablubb ...
        \newpage
        \subsection{First Subsection}
            dumdidum ...
    \section{Second Section}
        Blablablubb ...
        \subsection{Second Subsection}
            dumdidumdidum ...
\end{document}