当 changebar 延伸到整个页面时，\changebarsep 不起作用

Question

我用来\changebarsep调整changebar和textbody之间的间距。当changebar延伸到页面时，分隔设置不起作用，如附图所示。为什么？如何处理？

\documentclass[twoside]{article}
\usepackage[color]{changebar}

\begin{document}
\setlength\changebarsep{30pt}
%\setlength\changebarwidth{10pt}
\cbcolor{red}
This is some text.\\

\cbstart 
Here is some text that has to be marked with the usual changebar.
\cbend 

\vskip 45em
This is some further text.\\
%
\cbstart 
Here is some text that has to be marked with a different changebar.Here is some text that has to be marked with a different changebar.Here is some text that has to be marked with a different changebar.Here is some text that has to be marked with a different changebar.Here is some text that has to be marked with a different changebar.Here is some text that has to be marked with a different changebar.Here is some text that has to be marked with a different changebar.Here is some text that has to be marked with a different changebar.Here is some text that has to be marked with a different changebar.
\cbend

\end{document}