Fix layer visibility preservation
Fix layer visibility preservation

cignoni/meshlabjs,cnr-isti-vclab/meshlabjs,cnr-isti-vclab/meshlabjs,cignoni/meshlabjs,cnr-isti-vclab/meshlabjs,cignoni/meshlabjs,cignoni/meshlabjs,cnr-isti-vclab/meshlabjs,cignoni/meshlabjs,cnr-isti-vclab/meshlabjs