The color chooser dialog contains several controls that are not fully
accessible:

1. The 20 color squares in the Palette group box are all objects of unknown
role - they should probably have the role ATK_ROLE_PUSH_BUTTON

2. The Opacity slider is lacking an AccessibleRelation (the
LabelFor/LabeledBy relation) connecting it to the static text "Opacity:".

3. The custom control for manipulating color setting in color space (the
triangle inside the annulus), while wonderfully keyboard accessible (yea!),
doesn't implement ATK and therefore doesn't provide appropriate feedback to
the blind user when being manipulted from the keyboard.  This control
presents an interesting challenge (and we should probably discuss it some
in this bug report before anyone tries to implement anything).  The desired
feedback to the blind user when manipulating it is to have spoken (or
Brailled) the name or trio of HSV/RGB values when they change. 
AccessibleValue doesn't exactly work here as there are three (or six!)
values changing.  Perhaps we could set and re-set the AccessibleName -
synthesizing the color name as a best-match reverse lookup of RGB values in
the list of named X colors.  This feels like the best approach to me.  The
other challenge is for the low-vision user, who wants to have the little
white annulus within the color triangle always shown in the magnified view.
 At high magnification levels, the entire triangle won't fit within the
screen, so we want to pan the magnified view to that annulus.  So long as
the low-vision user uses the mouse to manipulate the control, mouse
tracking will work (making this a lower priority issue).  Still, it'd be
nice if our accessibility architecture could support this.


To experience these problems, run the color chooser under Gnopernicus with
speech (and Braille and magnification) feedback turned on.  Tabbing through
the items in the Palette will give you the speech feedback of "unknown"
each time a new color gets focus.  Likewise when you tab to the opacity
slider, you are only told "Slider current value <number>", and not "Opacity
slider current value <number>".  Finally, tabbing and manipulating the
color triangle/wheel gives you no feedback (besides "unknown").