Ubuntuphone Aquaris E 4.5 How to prevent webapps from stopping when losing focus?

I noticed that WebApps on my Aquaris E 4.5 Ubuntu Editon are somehow frozen when they lose the focus or when the phone goes on stand-by. This is annoying when e.g. an Internet Radio WebApp is pushed to the background and stops playing music. Even keeping it on top does not help because it will stop playing as soon as the phone switches to stand-by. Can this behaviour be influenced by a setting?