message: Fix `UsesTensorBasis` to return `false` on mixed meshes.
  Thanks !
diff: @@ -980,14 +980,14 @@ public:
  void Save(std::ostream &out) const;
  };
  +/// @brief Return true if the mesh contains only one topology and the elements are tensor elements.
  inline bool UsesTensorBasis(const FiniteElementSpace& fes)
  {
  - // TODO: mixed meshes: return true if there is at least one tensor-product
  - // Geometry in the global mesh and the FE collection returns a
  - // TensorBasisElement for that Geometry?
  -
  + Mesh & mesh = *fes.GetMesh();
  + const bool mixed = mesh.GetNumGeometries(mesh.Dimension()) > 1;
  // Potential issue: empty local mesh --> no element 0.
  - return dynamic_cast<const mfem::TensorBasisElement *>(fes.GetFE(0))!=nullptr;
  + return !mixed &&
  + dynamic_cast<const mfem::TensorBasisElement *>(fes.GetFE(0))!=nullptr;
  }
  }
  