options / arrow portion of combobutton needs an accessible name

[Becky Gibson]

There is currently no information spoken by screen readers about the arrow button portion of the combo button. This needs a name - I think this can be accomplished by adding a title to the button but needs more research and testing. This also has i18n issues.

[davidb]

Becky what do you think about adding: title="${caption}" to the template for the arrow button?

[Becky Gibson]

Caption refers to the information about the "default" part of the button. My preference is to add a new parameter to the combobutton and add that as the title of the arrow button. This would need to be documented as required for a11y in the button documentation. Possible names for this parameter would be optionsTitle or menuTitle. This would make the author responsible for the actual title and eliminate the need for i18n within the widget.

[davidb]

proposed fix (optionsTitle='foo' in combo buttons converts to title='foo')

[davidb]

Becky, Bill, this fix seems to work nice (tested with JAWS). I think the patch can go in (my sandbox diff's are getting noisy).

[Becky Gibson]

(In [8838]) changes by David Bolter to add title to arrow portion of combobutton for a11y fixes #3063