Following the most recent OTA update from Samsung (the second JellyBean update from Samsung) on my Galaxy SIII, as well as fixing a copy/paste issue, a new feature was introduced called “Multi-Window”. This new feature added a blue button to the side of the screen and allows fast switching of apps (I’m not aware that it does much more than that).
In any case, I found the feature more of an annoyance than something that I would want and use, and searched all over the place to turn it off. Internet searches yielded nothing (probably as a result of how new the feature is) and scouring the settings on the phone proved unfruitful.
Today, though, I found the toggle button I had been looking for. It has been added on to the end of the quick-toggle buttons on the phone’s notification panel (as seen in the screen shot). I’m much happier having it turned off.
Something worth noting, is that with multi-window mode enabled, holding the back button on the phone will hide the little blue tab. This may provide a suitable compromise between leaving the mode enabled but it not interrupting the normal use of your phone.
Below is are two examples of the dual screen in action. Using an email to check an address which can be put into Maps. The screenshot on the right shows the floating keyboard which is not attached to either of the two miniature screens. The keys on the floating keyboard are a little small and difficult to use though.