This command adds two complemantary options `hide` and `show` to the `todonotes` package. If `hide` is given then the todo note itself will not be rendered, but a index entry will be created. **Usage:** while this is not part of the `todonote` package you can insert this snippet in your preample *after* the package has been loaded.

hide_todonotes

\makeatletter
  \if@todonotes@disabled%
  \else
    \newif\if@todonotes@localhide\@todonotes@localhidefalse%
    \define@key{todonotes}{hide}[]{\@todonotes@localhidetrue}%
    \define@key{todonotes}{show}[]{\@todonotes@localhidefalse}%

    \renewcommand{\@todo}[2][]{%
    \if@todonotes@prependcaptionglobal%
      \@todonotes@prependcaptiontrue%
    \else%
      \@todonotes@prependcaptionfalse%
    \fi%
    \renewcommand{\@todonotes@text}{#2}%
    \renewcommand{\@todonotes@caption}{#2}%
    \setkeys{todonotes}{#1}%
    \if@todonotes@localdisable%
    \else%
      \addtocounter{@todonotes@numberoftodonotes}{1}%
      \if@todonotes@appendtolistoftodos%
        \phantomsection%
        \if@todonotes@captiongiven%
        \else%
          \renewcommand{\@todonotes@caption}{#2}%
        \fi%
        \@todonotes@addElementToListOfTodos%
      \fi%
      \if@todonotes@captiongiven%
        \if@todonotes@prependcaption%
          \renewcommand{\@todonotes@text}{\@todonotes@caption: #2}%
        \fi%
      \fi%
      \if@todonotes@hidden
        \@todonotes@localhidefalse
      \else
        \if@todonotes@inlinenote%
            \@todonotes@drawInlineNote%
        \else%
            \@todonotes@drawMarginNoteWithLine%
        \fi%\if@todonotes@inlinenote
      \fi%\if@todonotes@hidden
    \fi%\if@todonotes@localdisable
    }%renewcommand{\@todo}[2][]
  \fi%if@todonotes@disabled
\makeatother