What Am I doing wrong Droid 48

[Didier Lachieze]

With the free version you have to select “Save on exit” in the settings, and to use “Quit” to exit the application and to have the memory saved.
At least it’s how it works on my Android 5.1.1 phone.
I don't find a version that you can buy in the Android Play Store and the in-app donation is not working, so even if you want it's not possible to buy this app.