It's right here: http://gtkdcoding.com/2019/05/10/0034-accelgroup_singleton.html
Blog Post #0034 - A Singleton AccelGroup
Ron Tarrant via Digitalmars-d-learn Fri, 10 May 2019 02:26:03 -0700
In today's blog post is an example of how to use a singleton for
the AccelGroup, so you don't have to pass a reference down
through a gazillion levels to get it to the MenuItems.