InsertionGroup should not set/null Mesh property
InsertionGroup should not set/null Mesh property

jlewin/MatterControl,larsbrubaker/MatterControl,mmoening/MatterControl,jlewin/MatterControl,unlimitedbacon/MatterControl,jlewin/MatterControl,larsbrubaker/MatterControl,jlewin/MatterControl,mmoening/MatterControl,unlimitedbacon/MatterControl,larsbrubaker/MatterControl,mmoening/MatterControl,unlimitedbacon/MatterControl,larsbrubaker/MatterControl,unlimitedbacon/MatterControl