Screen Overlapping
iPhone 6s, iOS 9.3.5
Maybe you need to disable the 'transparency' setting of the Accessibility settings. Apple think it is a feature to see what is underneath the current view.
See the section 'Speed Up iOS 9 by Disabling Transparency & Motion'
http://osxdaily.com/2015/09/18/slow-ios-9-speed-up-tips/
Screen Overlapping