[Newbies] Dismissing an object

When we create an instance of a class with the new method, it does not show up in the world unless we use the openInWorld method. To make it disappear we tried dismiss me option from the halo menu. Does the dismissed object remain created somewhere in the background or does it get completely deleted from the system. Also, we have to ask, does evaluating (meaning repeatedly using the do it option) for the code which looks like this:className newCreate multiple objects of the same class in the background, or does it override the previously created object? Azka