This app was mentioned in 4 comments, with an average of 0.75 upvotes
You install it, you activate it, and it works. The only problem is that there's no way to launch apps in multi window mode.
What I did, was to download an app drawer app (must be full screen!) I picked this. You then add it to the whitelist, and tick "force multi window while there's a floating window open". Now, to launch floating apps, just launch them through that app drawer app.
I heard about this the other day. As for now I just toggle between home screen, favourites and this free app. https://play.google.com/store/apps/details?id=au.radsoft.appdrawer
I just installed "App Drawer" from the Play Store and accessed it from there.
https://play.google.com/store/apps/details?id=au.radsoft.appdrawer&hl=en
This change isn't targeted at you, but at new users. It's been posted several times before, but regular, non-techy new-to-Android users get confused with the concept of having a separate app drawer and a homescreen. They don't even know what an app drawer is for that matter. They think deleting an icon from the homescreen is equivalent to uninstalling an app, especially since when you install an app by default, it's shortcut gets placed on the homescreen. For simple, end users, that shortcut is the app.
As for us, well this doesn't really affect us, since we have the choice of using a different Launcher or homescreen. Heck, you can even keep Google Now Launcher (or your stock Launcher), and just use a third party app drawer.