code: public ElementUI materialize(ElementUI parent) {
          boolean isDesktop = parent instanceof ElementDesktop;
  
          if (isDesktop) {
              parent.getDefinition().initElement(parent, root);
          }
  
          materializeChildren(parent, root, !isDesktop);
          ElementUI element = parent.getLastVisibleChild();
          
          if (element != null) {
              element.getRoot().activate(true);
          }
  
          return element;
      }
docs: Materializes the layout, under the specified parent, starting from the layout origin.
  
  @param parent Parent UI element at this level of the hierarchy. May be null.
  @return The UI element created during this pass.