"One MIDI Editor per Project" not working. HELP

I don't understand what i've done wrong.

I'm trying to see multiple parts in the same midi editor. It's just not working. Kenny's videos are great but, I'm not getting it to work.

"One MIDI Editor per Project" + "Open all selected MIDI items"

I'm baffled. Any help?

"One MIDI Editor per Project" not working. HELP