show "continued" for nested description list item on page break

Question

I'm using enumitem to create a description list.

These lists can sometimes be nested and can get very long. When a list item with a lot of description text breaks over a page it is difficult to tell to which item the current description belongs.

In these cases, I would like to put a note at the top of the page that shows the preceding item name, "continued".

Here is a MWE. I have put in the textsuperscript text manually; what I would like to do is make that happen automatically any time the list goes over a pagebreak.

\documentclass{book}
\usepackage{enumitem}

\newlist{Options}{description}{5}
\setlist[Options]{topsep=0.25em plus 0.2em minus 0.1em,
        parsep=0.5\baselineskip plus .1\baselineskip minus .1\baselineskip,
        itemsep=0.25em plus 0.2em minus 0.1em,
        partopsep=0pt,
}
\newcommand*{\Option}[1]{%
    \item[#1]\mbox{}\newline%
}

\begin{document}

\begin{Options}
    \Option{first item} and explanatory text
    \Option{second item} and more text%
        \clearpage\textsuperscript{second item \emph{continued}}\newline%
        more text describing the second item.
    \end{Options}

\end{document}

Here is another case using nested options:

\begin{Options}
    \Option{first item} and explanatory text
    \Option{second item} and more text%
        \begin{Options}
            \Option{nested option} text
        \end{Options}

    text that belongs to \emph{second item}\clearpage
    more text about \emph{second item}

\end{Options}

Answer 1

You can do this using the atbegshi package, together with an \if... statement where you set the \if... equal to true at the start of the option and then to false at the end using \setlist.

Here's a MWE. I have used the same continuation message that you used above.

\documentclass{book}
\usepackage{enumitem}
\usepackage{atbegshi}

\newif\ifInOptions\InOptionsfalse
\newlist{Options}{description}{5}
\setlist[Options]{topsep=0.25em plus 0.2em minus 0.1em,
        parsep=0.5\baselineskip plus .1\baselineskip minus .1\baselineskip,
        itemsep=0.25em plus 0.2em minus 0.1em,
        partopsep=0pt,before=\InOptionstrue,after=\InOptionsfalse,
}
\let\lastOption\relax
\newcommand*{\Option}[1]{\def\lastOption{#1}% remember the option for continued...
    \item[#1]\mbox{}\newline%
}
\AtBeginShipout{\ifInOptions%
  \AtBeginShipoutNext{\textsuperscript{\lastOption \emph{continued}}\newline}%
\fi}

\begin{document}
  \begin{Options}
    \Option{first item} and explanatory text
    \Option{second item} and more text%
        \clearpage%\textsuperscript{second item \emph{continued}}\newline%
        more text describing the second item.
  \end{Options}
\end{document}

This even seems to play well with nested environments because the \ifInOptions is implicitly set within \begin{group}...\end{group}.