 Create an observer widget with the items:
TreeWidget* tree_widget = new TreeWidget(nodeA);
tree_widget->show();
\endcode

The resulting tree is shown below. Note that "Node C" contains categorized items while the other two nodes does not use categories. There is no limitation on combining different nodes. It is for example possible to attach an uncategorized node to a specific category in a categorized node.

\image html trees_simple_example_formatted.jpg "Formatted Tree Combining Categorized and Uncategor