Mac Mail - no share option in dropdowns

I just read that I can right-click a Mac Mail message in mail and use "Share" to add a message to Reminders. When I went to try it there is no Share option in any right-click menus, nor indeed anywhere in any of the Mac Mail menu-bar dropdowns - not even greyed out.

Share is available in other apps - Firefox, Safari, Preview, for example - but not in Mac Mail. Mac Mail is the default mailer.

Any ideas for getting Share back on the Mail right-click menu?

Big Sur 11.6.1

Mail 14.0

Thanks in advance.