How does Iphone6 close the recent call history in the background?

1. In the iOS8 interface, we click on the "Settings" icon in the main interface, as shown in the picture

2. Then we find the "mail, Address Book, Calendar" menu click on it to open.

3. Then enter the mail, Address Book, calendar, and then click the "Show in Application Switcher" detail as shown in the picture.

4. As shown in the diagram, we can set it in the "Show in Application Switcher".

5. Well, after we set up, you're pressing two home keys to see if we canceled something that doesn't show up here.