Nodes are elements (shapes and symbols) that make up a UML diagram. Nodes are the most important components of a UML diagram. All other components, such as paths and labels, help to describe nodes and relationships between nodes.

Each diagram type has a pre-defined set of commonly used node styles available in the style bar. Creating a node in your diagram is as simple as selecting a node style by clicking on the appropriate button, then clicking on the diagram.
For greatest convenience, the style bar allows you to choose a node style not only by buttons, but also by name using a drop-down box, by categorized drop-menu, or even by a dialog box that full illustrations and descriptions of all defined styles.
The styles that appear on buttons and in the drop-menu are configurable as are the number of buttons and their size.