1436552 - Port |bug 1428930 - Move as many XBL accessibility roles into XULMap.h as possible| to comm-central

Status: NEW

(Thunderbird :: Upstream Synchronization, task)

Description

[:Paolo Amadini]

At present I've only noticed that the "panebutton" binding in "common/bindings/preferences.xml" may be affected by the patch in bug 1428930. We didn't have to take care of this binding because we have already removed support for preferences windows entirely.

A simple workaround can be to change the code so the panebutton is bound to a tag that already gets the "xul:listitem" role thanks to the new tag mapping, instead of a custom tag.

Comment 1

[Richard Marti (:Paenglab)]

Paolo, please can you explain how this tagging goes and how to do it? My knowledge is not deep enough on this area.

Comment 2

[:Paolo Amadini]

As far as I understand it, the accessibility code mirrors the DOM tree of the document into a parallel accessibility tree, which is created by associating a "role" to each relevant element of the DOM tree, indicating for example if something is an input field or an image. This is used for example by screen readers to know how to treat each element.

For XUL, these roles were previously set by looking at the "role" attribute on XBL bindings, which were associated with specific element names using CSS. Bug 1428930 changes this to be more similar to what we do for HTML, where the local element name is the only information used to assign a role.

In the case of "panebutton", the "xul:listitem" role that was set using XBL is not recognized anymore:

https://dxr.mozilla.org/comm-central/rev/fdbbb8fee22945c32eeaaa83526b9ad4f360e99a/common/bindings/preferences.xml#1382

You can fix this by changing the element from "panebutton" to something like "listitem[type=panebutton]".

At the moment there are some roles that can still be specified using the "role" attribute, but we're removing support for this attribute completely well before we remove support for XBL in general.

Comment 3

[Delicia Wright]

Attachment: same problem

Thanks from ballraviti1971.