% experimental, based on an idea by Aditya, messed up by Hans.

\unprotect

\installnamespace{overview}

\installsimplecommandhandler \????overview {overview}

\initializeboxstack{\????overview}

\let\overviewsection\empty

\let\overview_previous_headnumber\!!minusone
\let\overview_current_headnumber \!!zerocount

\unexpanded\def\overview_save_page#1%
  {\ifx\overviewsection\empty
     \page_shipouts_normal{#1}%
   \else
     \xdef\overview_current_headnumber{\somenamedheadnumber\overviewsection\c!current}%
     \setbox\nextbox\hbox{#1}%
     \ifx\overview_previous_headnumber\overview_current_headnumber \else
       \glet\overview_previous_headnumber\overview_current_headnumber
       \setbox\scratchbox\copy\nextbox
       \cleanupbox\scratchbox % remove nodes that should not be seen in the backend twice
       \writestatus{overview}{saving first page of \overviewsection\space\overview_current_headnumber}%
       \savebox{\????overview}{\overview_current_headnumber}{\box\scratchbox}%
     \fi
     \page_shipouts_normal{\box\nextbox}%
   \fi}

\installshipoutmethod{overview}\overview_save_page

\definelistalternative
  [overview]
  [\c!renderingsetup=\??listrenderings:overview]

\setuplistalternative
  [overview]
  [\c!before=\dontleavehmode,
   \c!after=\space,
   \c!width=.4\textwidth] % or \listparameter\c!width

\startsetups[\??listrenderings:overview]
    \doifboxelse{\????overview}{\currentlistentrynumber}
       {\listalternativeparameter\c!before
        \startcurrentlistentrywrapper
          \scale
            [\c!width=\listalternativeparameter\c!width]
            {\foundbox{\????overview}{\currentlistentrynumber}}%
        \stopcurrentlistentrywrapper
        \listalternativeparameter\c!after}
       {}%
\stopsetups

\unexpanded\def\placeoverviewpage
  {\startstandardmakeup[\c!align=\v!middle]
      \placelist
        [\overviewsection]
        [\c!criterium=\v!all,
         \c!alternative=overview]
   \stopstandardmakeup}

\appendtoks
    \ifx\overviewsection\empty
      \edef\overviewsection{\overviewparameter\c!level}%
      \ifx\overviewsection\empty
        \setuppaper[\c!method=\v!normal]%
      \else
        \setuppaper[\c!method=overview]%
      \fi
   \else
     \writestatus{overview}{level is already set to \overviewsection, ignoring \overviewparameter\c!level}%
   \fi
\to \everysetupoverview

\protect

\continueifinputfile{m-pageview.mkiv}

\usemodule[pageview]

\setupinteraction
  [state=start]

\setupoverview
  [level=section]

\setuppapersize
  [S4]

\starttext

\dorecurse{4}
  {\startsection[title={Section #1}]
      \dorecurse{3}{\input knuth \par}
    \stopsection
  \page}

\placeoverviewpage

\stoptext