The Highlight command adds a background color to highlight all or part of the math in the active canvas element.   

The HighlightOff command removes the highlights added by a previous call to Highlight.

A "canvas" is an interactive section of a Maple document created by the NewCanvas command, or a shared web-based Maple Learn document.   See the Script command for a more complete description.

$\mathrm{with}\left(\mathrm{DocumentTools}:-\mathrm{Canvas}\right)\:$

$\mathrm{cv}≔\mathrm{NewCanvas}\left(\left[''Einstein''\right]\right)\:$

$\mathrm{ShowCanvas}\left(\mathrm{cv}\right)$

$\mathrm{sc}≔\mathrm{Script}\left(\right)\:$

$\mathrm{SetActive}\left(\mathrm{sc}\,''0:0''\right)$

$\mathrm{SetMath}\left(\mathrm{sc}\,E=m{c}^2\,'\mathrm{where}'=''below''\right)$

$\mathrm{Highlight}\left(\mathrm{sc}\,c\right)$

$\mathrm{Annotate}\left(\mathrm{sc}\,''the\; speed\; of\; light''\right)$

$\mathrm{HighlightOff}\left(\mathrm{sc}\right)$

$\mathrm{Highlight}\left(\mathrm{sc}\,m\right)$

$\mathrm{Annotate}\left(\mathrm{sc}\,''mass''\right)$

$\mathrm{HighlightOff}\left(\mathrm{sc}\right)$

$\mathrm{Highlight}\left(\mathrm{sc}\,E\right)$

$\mathrm{Annotate}\left(\mathrm{sc}\,''energy''\right)$

$\mathrm{HighlightOff}\left(\mathrm{sc}\right)$

$\mathrm{Annotate}\left(\mathrm{sc}\,''''\right)$

$\mathrm{cv2}≔\mathrm{NewCanvas}\left(\left[''Einstein''\right]\,\mathrm{sc}\right)\:$

$\mathrm{ShareCanvas}\left(\mathrm{cv2}\right)$

The DocumentTools[Canvas][Script][Highlight] and DocumentTools[Canvas][Script][HighlightOff] commands were introduced in Maple 2021.

For more information on Maple 2021 changes, see Updates in Maple 2021.