Sometimes, I want to mark a section of my manuscript for later inspection. So far I have been using a different color, but I really do not like it. I was wondering if I can draw a black strip on the margin. Ideally, it should work across pages and with equations. I believe it should be possible to do since draft mode already does something similar. But I do not know where to start.
MWE for testing:
\documentclass{article}
\usepackage{lipsum}
\newenvironment{marked}{}{}
\begin{document}
\lipsum[1-4]
\begin{marked}
\lipsum[5]
\[ x = y\]
\lipsum[6]
\end{marked}
\end{document}
Desired output:
leftbarenvironment from theframedpackage. – Bernard Nov 20 '17 at 10:12