How Solitaire drains your battery?

For a couple of days, I noticed that my batteries were draining quite rapidly. Indeed, both batteries went dead after a day of use only. I checked if any software was running in the background and found nothing. Yesterday I found the culprit. Before it all happen, I was playing Solitaire. When I got bored with the game, I naturally closed the application. Yesterday I decided to play Solitaire again and guess what? I started the game and found that the clock was still ticking. In other words, if you don't succesfully end the game or you decide to put it aside in the middle of a game, it doesn't really close. It keeps running in the background...invisible. Even Magic Button did not detect the still running Solitaire. Looks like a bug to me. To avoid that situation, I would tap on the New Game options under Menu and then close the application. It seems to be the only way to properly kill Solitaire.