Levels and random behavior of objects

[ridom]

Hello
First of all, congrats for the great software.
I start using it a week ago and still learning. Thus I have a question regarding levels and objects.
When I add a new level to the project some of the objects from the copied level reappear in the new one. First, I do not know why only some of them reappear. And second, if I try to delete them they are also deleted in the original level from where they were created. How can I deal with this?. Thx.

[Puybaret]

All object which top is higher than the elevation of the selected level appears in that level.