I tried fancytabs by the example given in its manual as
\documentclass{scrbook}
\usepackage{scrpage2}
\usepackage{fancytabs}
\usepackage{lipsum}
% Capture chapter head
\let\oldchapter\chapter
\newcommand\temphead{}
\newcommand\chaphead{}
\renewcommand\chapter[2][\temphead]{%
\renewcommand\temphead{#2}%
\renewcommand\chaphead{#2}%
\oldchapter[#1]{#2}}
% Set central right header to display tab
% for both scrplain and scrheadings
\cohead[\fancytab{\chaphead}{\thechapter}]
{\fancytab{\chaphead}{\thechapter}}
\renewcommand*{\chapterpagestyle}{scrplain}
\pagestyle{scrheadings}
\begin{document}
\chapter{A chapter}
\lipsum
\lipsum
\end{document}
but it does not show the vertical lab displayed in the manual document or HERE. I just copied the exact example from manual. Where did I do wrong?