@Nullable
    private StructureViewModel.ElementInfoProvider getElementInfoProvider() {
      if (myTreeModel instanceof StructureViewModel.ElementInfoProvider) {
        return (StructureViewModel.ElementInfoProvider)myTreeModel;
      }
      if (myTreeModel instanceof TreeModelWrapper) {
        StructureViewModel model = ((TreeModelWrapper)myTreeModel).getModel();
        if (model instanceof StructureViewModel.ElementInfoProvider) {
          return (StructureViewModel.ElementInfoProvider)model;
        }
      }

      return null;
    }
@Nullable
    private StructureViewModel.ElementInfoProvider getElementInfoProvider()