custom margin notes

Question

I am trying to set up a custom margin note command for my lecture notes but I encountered a few problems.

First of all, this is how it should look:

As you can see in the screenshot above, the margin notes are numbered (I tried to mimic footnotes).

First, I tried to use the marginpar command. Sadly, it cannot be used in math environments as well as tcbtheorem environments from the tcolorbox package which I happen to use quite frequently.

After trying with marginpar I ended up with the marginnote package, which does work in math as well as tcbtheorem environments, but there are different problems. The biggest downside is, that margin notes from the marginnote command overlap very easily and it's annoying to manually move them up and down until one finds the right spot.

What I am trying to achieve are numbered margin notes which can be referenced (used with the label/ref commands), used in math as well as tcbtheorem environments and don't overlap (they should behave like margin notes from the marginpar command, which automatically move up and down).

Is something like this achievable?

Minimal example (comment out mpar command to see errors):

\documentclass{article}

\usepackage[left=10mm,right=65mm,top=20mm,bottom=25mm,headheight=15pt]{geometry}
\usepackage{marginnote}
\usepackage[most]{tcolorbox}
\usepackage{blindtext}

\setlength{\marginparwidth}{50mm}
\setlength{\marginparsep}{5mm}

\newcounter{mnotecnt}
\renewcommand\themnotecnt{\textsuperscript{\arabic{mnotecnt}}}
\newcommand\mpar[1]{\refstepcounter{mnotecnt}\themnotecnt\marginpar{\footnotesize\themnotecnt\hspace{1pt}#1}}

\newcommand\mnote[1]{\refstepcounter{mnotecnt}\themnotecnt\marginnote{\footnotesize\themnotecnt\hspace{1pt}#1}}

\newtcbtheorem[]{mytheo}{Theorem}{}{thm}

\begin{document}

This is a sentence.\mpar{Margin note using the marginpar command.}
\blindtext

\begin{mytheo}{}{}
  This is a theorem.\mnote{Margin note using the marginnote package.}
\end{mytheo}

\section*{Problems:}

\begin{mytheo}{}{}
  This is a theorem.\mnote{marginnote} This is a sentence.\mnote{another one}
  (should not overlap!)
\end{mytheo}

\begin{align*}
  \alpha + \beta = \gamma%\mpar{Does not work.} % comment out for error
\end{align*}

\begin{mytheo}{}{}
  This is a theorem.%\mpar{Does not work.} % comment out for error
\end{mytheo}

\end{document}

Answer 1

The memoir class (a superset of book, report and article classes) provides a variety of what I called "page notes", which include footenotes, either at the page bottom or in the margin, or unnumbered notes in the margin which can extend for over multiple pages.

When using the article option memoir treats \chapter as \section, and \subsection as \section. and so on, so that a document initially written like a book can be typeset as an article. This was the initial idea for an easy conversion from book/report to article.

However there was no way to typeset an original article document using memoir except by editing the original document and changing all \section to \chapter, \subsection to \section, etc. The following MWE shows how you can use the memoir facilities on unedited article code.

% memarticleprob.tex  SE 630602

\documentclass[article]{memoir}
\let\subsection\section % undo article option change of divisions
\let\section\chapter    % ditto

\footnotesinmargin % set footnotes in the margin

\usepackage{lipsum}

\begin{document}
\tableofcontents

\section{First}
\lipsum[2]

Some sidefootnoted text.\footnote{Margined footnote.}

\lipsum[4]

Some sidefootnoted text.\footnote{Another margined footnote.}

\subsection{First sub}
\lipsum[2]
\footnotesatfoot % revert to bottom of page footnotes
Some footnoted text.\footnote{Footnote at bottom.}

\end{document}

Read the manual (texdoc memoir chapter "Page notes") for more on the page notes facilities.