This page shows you what the ▤ Menu key can do.
the ▤ Menu key is just fantastic.
In Firefox, you can press 【▤ Menu c】 to copy, and 【▤ Menu p】 to paste. Also works in terminal and most other apps.
In desktop (file manager), you can press 【▤ Menu r】 to rename, 【▤ Menu d】 to delete, 【▤ Menu p】 to show info/properties, etc.
This is particularly nice when your keyboard has a nice positioned ▤ Menu key.
The menu key isn't positioned in the best spot. You can make it so. Or, if your keyboard don't have the ▤ Menu key but have Fn instead, here's what you can do.
Buy one of the Batman Keyboards, so you can set a thumb key to do ▤ Menu.
You can make the Caps Lock to be the ▤ Menu key.
xmodmap. 〔➤ Linux: xmodmap Tutorial ⌨〕.
When you buy a keyboard, never get one that has Fn key in place of ▤ Menu key. Because, the Fn key is hardwired, you cannot remap in OS. If you don't like its preset multimedia functions, it becomes a useless key on one of the most important spot. Like, a dead horse squatting in front yard.
See: Emacs: How to Define Menu/App Keys.