FIX: MutationListener is not called twice anymore when adding a child object
FIX: MutationListener is not called twice anymore when adding a child object

Former-commit-id: 594cc0ec40db1bd7e6220a7c5bb392f1e7c97e21
hdeling/sofa,Anatoscope/sofa,hdeling/sofa,FabienPean/sofa,Anatoscope/sofa,FabienPean/sofa,Anatoscope/sofa,Anatoscope/sofa,FabienPean/sofa,hdeling/sofa,hdeling/sofa,FabienPean/sofa,Anatoscope/sofa,FabienPean/sofa,Anatoscope/sofa,FabienPean/sofa,hdeling/sofa,hdeling/sofa,Anatoscope/sofa,FabienPean/sofa,hdeling/sofa,hdeling/sofa,Anatoscope/sofa,hdeling/sofa,FabienPean/sofa,FabienPean/sofa,hdeling/sofa,Anatoscope/sofa,FabienPean/sofa