Applications do not close after exiting I have lately noticed that, after last updates on my Samsung S3 mini (although I am not entirely sure which ones in particular), applications simply do not close after exiting them and keep running in the background. As workaround I have to manually end all the processes from Task Manager.

I have read a couple of similar questions recommending this or that other Application Manager to switch them down but I did not understand whether this is a standard behaviour for Android phones (that I somehow never noticed) or a bug introduced.

Also, why is that so? Exit an application means exiting an application, I see no point is closing them but still keeping them running behind the back: it obviously drains the battery strongly. Is it adjustable?
I would suggest you use the Greenify app. It really shuts down or hibernates an app after you exit it. It doesnt allow the selected process to secretly run in the background.
You can find the app here.
The app works even better if the phone is rooted.