Authors using LaTeX to typeset books with significant margin
material often run into the problem of long notes running off
the bottom of the page. A typical workaround is to insert
\vshift commands by hand, but this is a tedious process that is
invalidated when pagination changes. Another workaround is
memoir's \sidebar function, but this can be unsatisfying for
short textual notes, and standard marginpars cannot be mixed
with sidebars. This package implements a solution to make
marginpars "just work" by keeping a list of floating inserts
and arranging them intelligently in the output routine.

Homepage:
https://ctan.org/pkg/marginfix
