Elements having problems on MacOS 10.11 El Capitan when working with layers.

I downloaded a trial version of photoshop elements. I began a project that involved working with layers. I am using OS X El Capitan. It appears to be incompatible with photoshop elements. The activity of photoshop elements in this environment is quite different than described in the documentation and instructional videos. When creating a new layer and dragging content to that new layer that new layer suddenly becomes the background and the original background layer disappears.