Anda_skoa Hi, thanks for responding so quickly.

This solution you offer me the thought too, but I have a problem with it, and then have to identify that or those created to allocate to other objects.

I have to create a multi editor tabs, and those singleton to create, I must assign dynamically to the current tab, so I find it very convenient to create them as singleton rather than as normal objects, it would have to inspect the object stack to verify if it exists, if it does not create it, and so every time you change tab, I think it's not a good idea to do so much unnecessary work that way also consumes resources.

Anyway, thank you very much for your contribution, I will continue investigating how to create these Singleton and when you have the answer I comment