W3C home > Mailing lists > Public > www-style@w3.org > June 2012

[css3-box] interactions of overflow-x and overflow-y

From: L. David Baron <dbaron@dbaron.org>
Date: Mon, 18 Jun 2012 13:27:32 -0700
To: www-style@w3.org
Message-ID: <20120618202732.GA17379@crum.dbaron.org>
http://dev.w3.org/csswg/css3-box/#overflow says:
  # The computed values of ‘overflow-x’ and ‘overflow-y’ are the
  # same as their specified values, except that some combinations
  # with ‘visible’ are not possible: if one is specified as
  # ‘visible’ and the other is ‘scroll’ or ‘auto’, then ‘visible’ is
  # set to ‘auto’.

I believe this should say that all combinations with 'visible' and
something else are not possible.  In other words, the current
wording allows 'visible' / 'hidden' combinations, but I think these
should not be allowed.

For a start, there are a whole bunch of behaviors in CSS that change
depending on whether overflow is 'visible' or has one of the other
values (in many cases, for good reason, since it doesn't make sense
to wrap text around floats that are scrollable relative to the
text).  It's not clear what should happen in all of these cases when
overflow is 'visible hidden' or 'hidden visible'.

Also, since we decided to change 'overflow: hidden' so that there's
internally a scrollable area and the element is programatically
scrollable (a change where Gecko was, prior to the change, the only
implementation that matched the spec), I think we should keep the
hidden, auto, and scroll values of overflow behaving pretty much the

I also don't think there are strong use cases for this combination.
If there are, I think those use cases should be described and
weighed against the costs and additional complexity of adding the


𝄞   L. David Baron                         http://dbaron.org/   𝄂
𝄢   Mozilla                           http://www.mozilla.org/   𝄂
Received on Monday, 18 June 2012 20:27:56 UTC

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