Voicing of slider / scale widget

[jbrugge]

We are trying to use a XUL scale widget in a Firefox extension we are
developing, and while it works well with the keyboard, it doesn't get
voiced correctly by JAWS, Window-Eyes or NVDA. With JAWS 8, for
instance, it will announce the slider and its initial value correctly
when you tab to the control, but as you adjust the value with the
arrow keys, JAWS voices the original value each time, not the updated
value. We have a text label next to the slider that we update with the
slider value in an onchange event handler, and that does show the
correct slider value as it updates.

I found a Bugzilla entry that looks like it may explain this (https://
bugzilla.mozilla.org/show_bug.cgi?id=493687), but the description is
short so I'm not positive that it would resolve this issue.

My questions, then, are:
1. Is this just a bug in the xul:scale widget, covered by the Bugzilla
entry?
2. Is there any workaround that would help JAWS or other screen
readers to be notified of the value changes?
3. What are useful alternatives to the slider to allow a user to
choose from a range of values? In this case we have 20 discreet
increments along the scale, which seems like too many for a drop-down
selection.

Thanks for any input or suggestions,
John