bool RebuildPropagationChains();
bool RemovePropagationChain (const TopoDS_Shape& theMainEdge);
bool BuildPropagationChain (const TopoDS_Shape& theMainEdge);
bool RebuildPropagationChains();
bool RemovePropagationChain (const TopoDS_Shape& theMainEdge);
bool BuildPropagationChain (const TopoDS_Shape& theMainEdge);