The ADD, PROPERTIES, and DELETE button shortcuts in the Variable Tab do not work. You can push ALT+A, ALT+P, or ALT+D OR CTRL+A, CTRL+P, or CTRL+D, but you won't get the desired effect.
ALT+A opens properties (not sure how this happened as there is no A in properties)
ALT+P opens the Scope Tab (ALT+P also represents the Scope Tab shortcut)
ALT+D opens the Debug Menu (ALT+D also represents the Debug Menu shortcut)