From JAXXWiki

You may come across a page flagged with the following message:

This component is fully supported by JAXX's default component support. As long as you know its API (and the general rules followed by DefaultComponentHandler) you know everything there is to know about using it as a tag. The documentation provided here is merely a convenience. What does this mean?

What does it mean?

Most of the properties of a component can be supported automatically. For instance, when JAXX sees the attribute text="Sample Text" on a class tag for a component with a method named setText(), it maps the attribute to the Java code setText("Sample Text"). Because Java objects follow standard naming conventions, such automatic default behaviors are sufficient to take care of most of an object's basic features.

Ideally, this default component support (provided by DefaultComponentHandler) would always be sufficient to support every feature of every class. Unfortunately, in real world components a few tweaks or additions are often necessary, or at least desirable, and so many of the Swing components supported by JAXX have custom handlers (which subclass DefaultComponentHandler) that add additional features which would otherwise be unavailable.

If you see the message above on a JAXX tag, it means that JAXX did not require any special behaviors for the component in question; it is fully supported by DefaultComponentHandler. Because DefaultComponentHandler follows well-defined rules (such as mapping text="Sample Text" to setText("Sample Text") above), you need only know those rules in order to know how JAXX will handle the object. Knowing the general rules is much more useful than knowing the specifics of how those rules apply for each and every class, as it is much less information to remember, and will be useful when dealing with a component that is not documented on this site (for instance your own custom components).

So, if you see this message, it means that you don't actually have to read the documentation for that specific tag -- its supported features will be obvious as long as you are familiar with its API and how DefaultComponentHandler works.