The "activedescendant" attribute

-	I don't understand the need for this attribute and think that it should be 
	deprecated.  Use of the "Roving TabIndex Technique" as a means of 
	managing a widget's active descendant is a much better backward and forward
	compatible solution.  I wrote up a blog entry on this topic back in Feb., 
	you can find my arguments against the "activedescendant" attribute here:
	
	http://yuiblog.com/blog/2009/02/23/managing-focus/


Section 4.3 Categorization of Roles

-	Currently there is a typo in the list that introduces the six categories.  
	The item labeled "Specialize Regions" should be "Application Structure"
	
-	I think that the current categorization of ARIA roles could be further
 	simplified, and as a result, improved.  My suggestions are to:

	1.	Kill the "Application Structure" category and combine what is currently 
		"User Input Widgets," "User Interface Elements," and 
		"Application Structure" into a single category called "Widgets".
		
	2.	Pull the "application" role from the "Landmark Roles" category and 
		create a new category called "Specialized Regions" that includes just
		the roles of "document" and "application"--since these two roles are 
		truly "special" in that the set/control the overall context the user 
		is working in.  They're also "special" in that they can be used to 
		control weather or not a screen reader's virtual buffer is toggled 
		on or off.
	
	This would leave five categories of ARIA roles:

		1.	Base Types
		2.	Widgets
		3.	Document Structure
		4.	Landmark Roles
		5.	Specialized Regions

-	There are a handful of ARIA roles that I believe should be either removed 
	or deprecated, as they duplicate rather than supplement native language 
	semantics.  The roles I would remove or deprecate are:
	
	-	img
	-	separator
	-	heading
	-	link
	-	list
	-	listitem

	**	The removal of these roles is important considering that their presence 
		seems to contradict the intend use of ARIA as mentioned in section 
		1.2 of the specification titled "Use Cases" which says: "ARIA is 
		intended to be used as a supplement for native language semantics, 
		not a replacement"
		
-	With all of the above changes in place, this is how I would see the 
	breakout of the individual roles:

	-	Base Types (unchanged)

	-	Widgets

		-	checkbox
		-	combobox
		-	input (abstract role)
		-	listbox
		-	option
		-	radio
		-	radiogroup
		-	range (abstract role)
		-	select (abstract role)
		-	slider
		-	spinbutton
		-	textbox
		-	button
		-	menu
		-	menubar
		-	menuitem
		-	menuitemcheckbox
		-	menuitemradio
		-	tablist
		-	tabpanel
		-	tab
		-	toolbar
		-	tooltip
		-	tree
		-	treegrid
		-	treeitem
		-	alert
		-	alertdialog
		-	dialog
		-	log
		-	marquee
		-	progressbar
		-	status
		-	timer


	-	Document Structure

		-	article
		-	columnheader
		-	definition
		-	directory
		-	grid
		-	gridcell
		-	group
		-	math
		-	note
		-	presentation
		-	region
		-	row
		-	rowheader
		-	section (abstract role)
		-	sectionhead (abstract role)


	-	Landmark Roles

		-	banner
		-	complementary
		-	contentinfo
		-	main
		-	navigation
		-	search


	- Specialized Regions
	
		-	application
		-	document