So where does this leave us regarding "merging" accordion and tab panel into a single ARIA role? If there is a different method required to open the panel in the accordion case vs the tab panel case then we will need AT to announce something different when focus reaches this item or users will not be able to operate the control.
The current proposal does not give AT this opportunity as the single select Accordion case does not have any properties which differ from the tab panel case.

If we don't include the auto-expand capability we will also need to consider what happens if the focus is on an unexpanded accordion header but there are subsequent accordions already expanded in the accordion.

regards,
James

David Bolter wrote:

Joseph Scheuhammer wrote:

    * *Tab*
          o When on an Accordion Header / Tab, each press of the tab key will
            move the input focus in the following manner:
               1. ...
               2. Focus moves to the first interactive element in the Tab page
                  or accordion panel. If the accordion panel for the currently
                  selected accordion header is not visible pressing Tab will
                  cause the accordion panel to expand.
               3. ...

Specifically, if focus is on an accordion header, and the associated tabpanel is 
not shown (aria-expanded = false), a Tab keystroke will open the associated 
tabpanel, and move focus to the first focusable item therein.

Note on terminology:  "accordion" is a multi-selectable tablist; "tabbed pane" 
is a single-selectable tablist.

After thinking about it, I don't think (2) above is right.  When a sighted user 
hits Tab, they usually have some idea of where they are going to end up.  They 
can see the next thing in the tab order.  If the accordion tabpanel is closed, 
the expectation would be to navigate to the next focusable visible item in the 
tab order.  Moving focus to something that is invisible would be jarring (even 
if it's made visible in the process).


I agree on this point. If the user hits space and expands the panel
first, fine, tab can then move to/within the panel, but not otherwise.

cheers,
David

James Nurthen | Project Lead, Accessibility
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