Bruno, as I suspected the leak during operations involving undo, ecosystems and moving objects around various layers are all probably inter-related with the primary culprit being the "undo" system. I suspect that e-on has implemented the undo system by keeping around multiple instances of the GDI objects (e.g. the graphical representation of the objects in the scene) so that it can quickly re-create the scene during an undo operation without having to rebuild the GDI object hierarchy. Which explains why Tom's idea would work since clearing ecosystems would clear all their representative GDI objects. So essentially, the leak isn't really a leak but more of a GDI overload in order to preserve faster display refresh following undo operations. The best workaround for this is to save your scene - quit Vue - resart and reload. This clears out the GDI stack and replaces it with a fresh one with no undo instances lying around. The ultimate solution for this would be for e-on to devise a new undo system which would rebuild the GDI object list rather than revert to old instances lying around. This would obviously be slower but would eliminate the GDI overloading situations.