I got this Note 8 recently when it was offered on Woot.  It has 4.4.2 on it.  I am just now getting to play with the thing and noticed this multi window feature in the tutorials. However, I can't seem to access the multi-window, or at least, I can't access the multi window the same way that is appears everyone else can.  I press the back button and hold it and a side bar appears (on the right side, and not the left side, and I can't move it as I have seen it moved in tutorial videos) with some apps on it, disappears quickly and does not leave a 'tab' as I have seen in pictures or tutorials.  I tried samsung support, and, of course, they suggested the factory reset (I did it twice, still same).  I even didn't allow it to reinstall anything the second time (skipped all the google set up, etc)  in case it was some app I had downloaded that is causing the problem, but no luck.  Has this happened to anyone and does anyone have a suggestion as to what this might be?  It seems to be the multi window because I can press an app on this 'sidebar' (If I am quick enough before it disappears) and press another and it will show them to me in a split screen, but this isn't the right functionality.  :'(