174919 - Implement EVENT_SHOW and EVENT_HIDE

Status: RESOLVED WORKSFORME

(Core :: Disability Access APIs, defect, P2)

Description

[Aaron Leventhal]

All elements can be hidden with visibility:hidden/collapsed or display:none. XUL
elements can also be hidden with the hidden or collapsed attributes.

We should be firing EVENT_SHOW or EVENT_HIDE when this happens.

I suggest we use DOMAttrModified to implement EVENT_SHOW and EVENT_HIDE for xul
elements. However, I'm not sure what kinds of events, if any, are filed for
visibility style changes or display style changes. We might need to create
custom events.

Comment 1

[Aaron Leventhal]

I've been told that AT vendors on Windows don't listen to EVENT_SHOW and
EVENT_HIDE, because of stability issues with using these events. I wonder if the
stability issue is still a problem.

In any case, there is no such known problem under ATK -- so we should implement
it for that.

Bill - would you agree these are important events to implement? Actually, does ATK 
just use EVENT_REORDER for all the mutations, including when stuff is shown or
hidden?

Comment 2

[Aaron Leventhal]

In MSAA there's also EVENT_CREATE and EVENT_DESTROY -- I think those are the
ones that cause stability issues.

Comment 3

[alexander :surkov (:asurkov)]

I think worksforme because these events are fired (gecko - show/hide/reorder, atk - chilren_changed, msaa - reorder). Right?