How to properly close a program in Samsung Galaxy S3? Possible Duplicate:
  What is the right way to close apps in Android?  




After using my Samsung Galaxy S III for a while, closing apps and dialogs with the "back" button (front-right), I pressed and held the front-middle button, which brought up a list of all windows and apps I had been using.

I suppose that means that they were still running in the background. How to close them properly?
What you see there is the list of Last Recent Used apps, they are suspended, but all or most program code is still cached in RAM, so it's fast to restart them. Don't worry about running out of RAM, if a new app needs it, this pages will be freed and used.