@Nullable
  IProperty getSelectedProperty() {
    ResourceBundleEditorViewElement first = getSelectedNodes()
      .filter(AbstractTreeNode.class)
      .filterMap(AbstractTreeNode::getValue)
      .filter(ResourceBundleEditorViewElement.class)
      .first();
    return first instanceof PropertyStructureViewElement ?
           ((PropertyStructureViewElement)first).getProperty() : null;
  }
@Nullable
  IProperty getSelectedProperty()