I have a strange behaviour with the object 'Continuous2D' and its function remove(object o).

Once I have populated my 2D space with objects, when using the remove(object o) method, it does
not guaranty me to unregister the object from the 2D space.
I even have some flip-flop behaviours with certain agents coming and going from my display.

Is there someone who has already experienced this behaviour ? how can I fix it ?