i used this religiously on Note 3 to have an app running in the background and opening a window up on top of it with a new app. it seems this app doesnt work with Note 5's. very disappointed. anyone know of a similar app that can accomplish this?
Not that I've seen. You can launch the app you want and then make into a floating window (if supported) by swiping diagonally from a top corner towards the opposite bottom side, but that's about it.
If I understand you correctly you are right, the Note 5 is different.
On the note 2 if I opened an app not supported by multi window, then opened an app that is supported, they would both be on screen.
On the Note 5 it says something like this app doesn't support multi window.
I believe that most (if not all) multiwindow apps support this now in the Note 5. So as long as the app shows in the multiwindow menu (or it shows the little 'two screen' icon on top of the app in the multitasking switcher) you should be able to do that or minimize the window into a floating icon.