I searched in the documentation and could not find this.
The recommended way to create a dialog for a component is using CRXDE Lite to build the JCR nodes and properties. We show this in multiple articles -- such as this one:
http://helpx.adobe.com/experience-manager/using/creating-aem-multifield-components.html
I will bring this issue up with the doc team and the community teams. We will look at writing a community article around building a component using XML as opposed tp nodes and properties using CRXDE Lite.