Help using documentation

I can't figure out how to determine available methods and properties for anything. Let's take AW.UI.Radio. It has a method called getSelectedItems for instance. Can't seem to corrolate that to ANYTHING in documentation section. When i pull up that class there are methods listed but the list isn't complete. Crawling up the hiearchy doesn't seem to have any references to that method either. Is the documentation that bad?

I'm thuroughly confused and getting by on examples only.

Go to AW.UI.Radio

http://www.activewidgets.com/aw.ui.radio/

Click on selected (Models section)

http://www.activewidgets.com/aw.ui.list/selected-model.html

Click on items (Properties section)

http://www.activewidgets.com/aw.ui.list/selected-items.html