List of todos breaks with ocgcolorlinks

Question

When trying to use \listoftodos with colorinlistoftodos and ocgcolorlinks, text disappears from the list of todos. To be precise, the text is still there, I can copy it, but cannot see it – it becomes transparent. Without the colorinlistoftodos option or without ocgcolorlinks, everything works fine.

Why is this happening? Is there any workaround?

MWE:

\documentclass{article}

\usepackage[utf8]{inputenc}
\usepackage[colorlinks]{hyperref}
\usepackage[ocgcolorlinks]{ocgx2}
\usepackage[colorinlistoftodos]{todonotes}

\begin{document}

Testing \todo{This is a todonote.}

\listoftodos

\end{document}

Answer 1

This is an edge case for ocgx2 with the ocgcolorlinks option, see https://gitlab.com/agrahn/ocgx2#package-option-ocgcolorlinks

Graphical objects in the link text need to be protected with command \ocglinkprotect{...}.

In the code below, the corresponding command from the todonotes is patched accordingly:

\documentclass{article}

\usepackage[utf8]{inputenc}
\usepackage{hyperref}
\usepackage[ocgcolorlinks]{ocgx2}
\usepackage[colorinlistoftodos]{todonotes}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\makeatletter
\renewcommand{\@todonotes@addElementToListOfTodos}{%
    \if@todonotes@colorinlistoftodos%
        \addcontentsline{tdo}{todo}{%
            \ocglinkprotect{\fcolorbox{\@todonotes@currentbordercolor}%
                {\@todonotes@currentbackgroundcolor}%
                {\textcolor{\@todonotes@currentbackgroundcolor}{o}}}%
            \ \@todonotes@caption}%
    \else%
        \addcontentsline{tdo}{todo}{\@todonotes@caption}%
    \fi}%
\makeatother
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\begin{document}

Testing \todo{This is a todonote.}

\listoftodos

\end{document}

Another option could be hyperref option linktocpage, which turns only the page numbers into hyperlinks.