[css-multicol-1] abspos boxes inside spanner

Fixes: #5612 specifying that spanners become the containing block for abspos boxes.

Author: rachelandrew

css-multicol-1/Overview.bs

@@ -184,7 +184,7 @@ Introduction</h2>
 <h3 id="values">
 Value Definitions</h3>
 
-	This specification follows the <a href="https://www.w3.org/TR/CSS2/about.html#property-defs">CSS property definition conventions</a> from [[!CSS2]]
+	This specification follows the <a href="https://www.w3.org/TR/CSS2/about.html#property-defs">CSS property definition conventions</a> from [[!CSS21]]
 	using the <a href="https://www.w3.org/TR/css-values-3/#value-defs">value definition syntax</a> from [[!CSS-VALUES-3]].
 	Value types not defined in this specification are defined in CSS Values &amp; Units [[!CSS-VALUES-3]].
 	Combination with other CSS modules may expand the definitions of these value types.
@@ -284,7 +284,7 @@ The Multi-Column Model</h2>
 	[=fragments=] and continues in the next [=column box=].
 
 	Note: Column boxes, which are [=anonymous boxes=],
-	do not become the containing block
+	do not become the [=containing block=]
 	for [=absolutely positioned boxes=].
 	The 'position' property, which establishes a containing block for such boxes,
 	applies to the [=multicol container=], it being the [=principal box=].
@@ -1104,8 +1104,10 @@ Spanning Columns</h2>
 	An element that spans more than one column is called a <dfn export>spanning element</dfn> 
 	and the box it creates is called a <dfn export>spanner</dfn>.
 
+	The spanner becomes the [=containing block=] for [=absolutely positioned boxes=] inside the spanner.
+
 	A spanning element is taken [=out-of-flow=], leaving a forced break. 
-	This does not affect the <a href="https://www.w3.org/TR/CSS2/zindex.html">painting order</a> [[!CSS21]] of the spanning element. 
+	This does not affect the <a href="https://www.w3.org/TR/CSS2/zindex.html">painting order</a> [[!CSS21]] of the spanning element.  
 
 	<div class="example">
 		In this example, an <code>h2</code> element has been added to the sample document after the sixth sentence 
@@ -1278,7 +1280,7 @@ Filling Columns</h2>
 	</pre>
 
 	This property specifies whether content
-	in a [=multi-column line=] that does <em>not</em> immediately preced a [=spanner=]
+	in a [=multi-column line=] that does <em>not</em> immediately precede a [=spanner=]
 	is balanced across columns or not.
 	The values are:
 
@@ -1571,6 +1573,16 @@ Pagination and Overflow Outside Multicol Containers</h3>
 
 This appendix is <em>informative</em>.
 
+<h3 id="changes-from-20191015">Changes from the <a href="https://www.w3.org/TR/2019/WD-css-multicol-1-20191015/">Working Draft (WD) of 15 October 2019</a></h3>
+
+<ul>
+	<li>Added the text "The spanner becomes the containing block for absolutely positioned boxes inside the spanner.". <a href="https://github.com/w3c/csswg-drafts/issues/5612#issuecomment-715369246">Resolved 23 Oct 2020</a>
+	</li>
+	<li>Adding the text "This property specifies whether content
+	in a multi-column line that does <em>not</em> immediately precede a spanner
+	is balanced across columns or not." <a href="https://github.com/w3c/csswg-drafts/issues/4689#issuecomment-621281467">Resolved 29 April 2020</a></li>
+</ul>
+
 <h3 id="changes-from-20180528">Changes from the <a href="https://www.w3.org/TR/2018/WD-css-multicol-1-20180528/">Working Draft (WD) of 28 May 2018</a></h3>
 <ul>
 	<li>Removed the non-normative text 

css-multicol-1/issues-april-2020.txt renamed to css-multicol-1/issues-dec-2020.txt

@@ -457,10 +457,18 @@ Issue 55.
 From:     Rachel Andrew
 Summary:  Defining what happens with column-fill in unconstrained containers for continuous and fragmented contexts
 Comments: https://github.com/w3c/csswg-drafts/issues/4689
-Open:     On face to face agenda
+Closed:   Accepted
+Resolved: https://github.com/w3c/csswg-drafts/issues/4689#issuecomment-621281467
 ----
 Issue 56.
 From:     Gérard Talbot
 Summary:  Improve column-fill example 26 and 27
 Comments: https://github.com/w3c/csswg-drafts/issues/3700
 Open:     Waiting for resolution to 55.
+----
+Issue 57.
+From:     Alison Maher
+Summary:  Improve column-fill example 26 and 27
+Comments: https://github.com/w3c/csswg-drafts/issues/5612
+Closed:   Accepted
+Resolved: https://github.com/w3c/csswg-drafts/issues/2203#issuecomment-431783027