Currently when mirroring a component it creates a new instance and not a copy thus:
1. the mirror component does not share the same geometry
2. in drawing instead of having 1 component with a quantity of 2 you have 2 components with a quantity of 1
2015 this was already brought up - might be a good idea to implement this.
The mirror command could be enhanced to work as it is right now so you can copy a component as a new think to manipulate just that one and also offer a mirror output that makes only a new instance of the same component.