Q: All App windows gather on one screen after sleep.

I am using two separate AOC displays on a Mac Mini running El Capitan 10.11.4 (just updated). The monitors were new to me at the time of El Capitan launch. The PROBLEM is that as soon as my monitors go to sleep all windows gather onto the home screen. This is a serious problem as my screen sleeps often during the day, but even if it was only once a day that's too often to reorganize all my applications. If this is a problem particular to AOC I will have to return these very nice anti-blue monitors. (After trying to find a solution on-line I found an app called STAY that is supposed to re-organize all windows with a single click in the Restore menu, but that's still every-time I wake the computer. I think there should be an internal solution? I've been using 2 monitors for many years and this is the first time I've run into this problem. Help!