Re: [csswg-drafts] [css-contain] Is it ok that contain:layout is a CB for fixpos/abspos descendants but doesn't establish a stacking context?

RE how tied together they are:

Right now, the [CSS painting order algorithm]( has three different mentions of a special category: `positioned descendants and descendants which actually create a new stacking context`.

Fun fact: up until now, this category has basically been 100% equivalent to "the set of all elements that establish a containing block for abs-pos descendants".  (Please correct me if I'm wrong, but I'm pretty sure these are 100% equivalent!)  However -- with the current contain:layout spec-text, these two categories will be slightly disjoint.  Specifically, `contain:layout` elements will be in the latter category (they establish a containing block) but they might not be in the former category (they're not necessarily positioned themselves, nor do they create a stacking context).

So I think the questions here are:
 - In the CSS Painting Order algorithm, would we want `contain:layout` elements to be included or excluded from the pieces about "positioned descendants and descendants which actually create a new stacking context"?  (And to what extent does this matter?)
 - Does this matter enough to create this new special-case (things which **are** abpsos containing blocks but **are not** themselves positioned nor do they form stacking contexts)?

GitHub Notification of comment by dholbert
Please view or discuss this issue at using your GitHub account

Received on Friday, 20 July 2018 21:49:08 UTC