Singleton question

[mark goldin]

Here is my singleton:
[Bindable]
public class ModelLocator extends EventDispatcher implements IModelLocator
{
private static var _instance:ModelLocator = new ModelLocator();
public var test:String;

public function ModelLocator()
{
if (_instance != null){
throw new Error("You can have only one ModelLocator");
}
}
 public static function getInstance():ModelLocator
{
 return _instance;
}
 }
}

When I am debugging I see that _instance is always different object when I
get an instance of my singleton. Is that right?

Thanks