Screen Overlay Detected

[pauljbm]

I would much appreciate any advice on how to understand and get rid of this problem. An example is when I attempt to change my lock screen wallpaper I get the message: Allow Themes to Access the SD card? I select allow. This leads to Screen overlay detected. I select Open settings. This leads to Draw over other apps. I select Themes and change No to Yes. Next I get an Attention message saying not allowing call and contacts permissions will render the themes app unusable. I select settings which takes me into App info. Themes with only the option to Force stop. And so it goes round again.