Q: close apps to save space

It's iOS multitasking

Double-tap home button. Then hold down an app, then a red minus will appear. Tap that to close that app.

JanMP wrote:

 

... Does anyone know anything about this?

Understanding the Task Bar...

http://support.apple.com/kb/HT4211

Closing apps doesn't save space. They're still stored on your iPad. Closing apps can free up memory, but the OS handles that automatically, so usually is not necessary.

To completely close an app, double-tap the home button to reveal the list of Recently Used apps. Press and hold on an icon until they jiggle, then tap the red - to close the app.

As mentioned, this is normally not necessary, unless you have a specific problem like an app freezing.

It's a -, not a X

Indeed it is. I was thinking of the delete app icon. Corrected my post.