Destruction symbol

[zyx]

Hello all,

     I apologize for my bad english. I have a doubt. Always when I create a new object, in a sequence diagram, by means of a construction (new) message, the object lifeline ends with a "X" - like the object has been destroyed. Why it happens? Is it always necessary?

[KP]

There is an option to switch it off:

ribbon | Start | Preferences | Diagram | Sequence | Garbage Collect (auto delete)

[zyx]

Right, its work. But why is it a default option? Why after the object had been create he is destroyed? I think I am loosing something here...