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UA Guidelines conflict: All content versus Limited Viewports (checkpoint 4.16)

From: Ian Jacobs <ij@w3.org>
Date: Fri, 07 Jul 2000 15:42:34 -0400
Message-ID: <396632AA.EBE8BE68@w3.org>
To: w3c-wai-ua@w3.org

I'm working on a new draft that I will publish later this
afternoon. I'm reading the checkpoints to see how they
fit together. So far, so good, but I have stumbled across
a problem. In the 10 June Guidelines [1], we have the following

   2.1 Make all content available through the user interface. [P1] 
       Users must have access to the entire document object, 
       including equivalent alternatives for content, attributes,
       style sheets, etc. through the user interface. This
       checkpoint does not require that all content be available 
       in every view. A document source view is part of a 
       solution for providing access to content, but is not 
       a sufficient solution on its own.

  4.16 Allow the user to configure the user agent to limit 
       the number of open viewports. [Priority 2] 

We have discussed that the minimal requirement for 
checkpoint 4.16 is to limit the number of open viewports
to one (refer to "Determining Conformance to UA Guidelines" [2]).

Checkpoint 4.16 is broken for the following reasons:

1) The definition of "viewport" includes frames. Therefore,
   this checkpoint would mean that a user agent could be 
   configured to render no more than one frame.

2) If the user has requested only one viewport, 
   and the user agent is not required to make all
   content available in a single viewport, then there's a 
   risk that the user will not have access to all content. 

3) There's no requirement on the user agent to notify the
   user that the user agent has suppressed the opening
   of a viewport.

Recall that the purpose of this checkpoint is to improve
accessibility for users who might be disoriented by 
the simultaneous presentation of too much content. This
checkpoint is not about disorientation due to sudden
focus changes (that's checkpoint 4.15). 

In the Proposed Recommendation [3], the checkpoint reads:

  4.16 For those viewports, prompts, and windows that 
       open without an explicit request from the user, 
       allow the user to configure how they open. 

To address the above issues, I propose that we rewrite 
4.16 as follows:

Allow the user to configure the user agent to only
open viewports on explicit user request. For a viewport
that the user agent does not open automatically, 
notify the user and allow the user to open the viewport
manually. Allow users to close viewports.


1) Some viewports may open and close in groups, like frames.
2) Following a link constitutes an explicit request, even
   though the user may not know that the author has programmed
   the link to open a new viewport. In this case, the user
   can close the viewport manually.
3) Executing scripts that cause a window to open do not
   constitute an explicit request from the user. 

 - Ian

[1] http://www.w3.org/WAI/UA/WD-UAAG10-20000610/
[2] http://www.w3.org/WAI/UA/2000/05/ua-minreqs
[3] http://www.w3.org/TR/2000/PR-UAAG10-20000310
Ian Jacobs (jacobs@w3.org)   http://www.w3.org/People/Jacobs
Tel:                         +1 831 457-2842
Cell:                        +1 917 450-8783
Received on Friday, 7 July 2000 15:42:38 UTC

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