Re: [css-containment] ED of Containment ready for review (was overflow:clip)

"The element must not provide a scrolling user interface"

This is rough - I'm guessing there's a terrible hidden cost in enabling
scrolling?


On Sun, Nov 10, 2013 at 9:05 AM, Tab Atkins Jr. <jackalmage@gmail.com>wrote:

> On Fri, Nov 8, 2013 at 4:03 PM, Simon Fraser <smfr@me.com> wrote:
> > On Nov 8, 2013, at 2:33 pm, Tab Atkins Jr. <jackalmage@gmail.com> wrote:
> >> The ED for the 'contain' property is now ready for review and possible
> >> WD publication: <http://dev.w3.org/csswg/css-containment/>.
> >>
> >> This is the property that originated as my suggestion for "overflow:
> >> clip", for stronger layout isolation.  As discussed on this list, it
> >> grew a bit to encompass more than just overflowing, so that using the
> >> property actually isolates the element's subtree *completely*
> >>
> >> Please review and let me know if I missed anything, or if there's
> >> anything that's not sane there.
> >>
> >> If you have good suggestions for how to split the containment up into
> >> a few pieces, and good justification for why you'd want this
> >> (preferably pointing to something real-world that could benefit from
> >> being isolated but needs to violate some of the assumptions of strict
> >> containment), we can make the property alternately accept a few
> >> feature keywords that turn on isolation per-feature.
> >>
> >> I'm aiming for a WD request in the next week or so, so review soon is
> >> appreciated!
> >
> > It’s unclear to me if “contain: strict” is a hint from the web author to
> the UA
> > to say that the set of conditions given in the spec are true, or whether
> > it actually causes all those conditions to be enforced.
> >
> > I suspect that it’s the former, but does this allow the UA to just render
> > incorrectly if the author says “contain: strict” but the conditions are
> not met?
> > That’s pretty weaksauce.
>
> There's a whole bunch of "must"s in there, saying exactly what the UA
> has to do, and at least a few of the restrictions don't make any sense
> as self-imposed restrictions.  I'm not sure how to make it clearer
> that this property causes behavior changes.
>
> ~TJ
>
>