[css-multicol-1] Out-of-flow elements and column balancing

Fixes #6279

Author: rachelandrew

css-multicol-1/Overview.bs

@@ -322,6 +322,9 @@ The Multi-Column Model</h2>
 		</figure>
 	</div>
 
+	Out-of-flow descendants of a [=multi-column container=] do affect column balancing, 
+	and the block-size of the [=multi-column container=].
+
 	The column boxes are ordered
 	in the [=inline base direction=] of the multicol container
 	and arranged into <dfn lt="multi-column line | multi-col line | multicol line">multicol lines</dfn>.
@@ -1545,7 +1548,9 @@ This appendix is <em>informative</em>.
 <h3 id="changes-from-20210212">Changes from the <a href="https://www.w3.org/TR/2021/WD-css-multicol-1-20210212/">Working Draft (WD) of 12 February 2021</a></h3>
 
 <ul>
-	<li>Adds the text, "The margins of two spanners separated only by an absolutely positioned item will collapse with each other, 
+	<li>Added the text "Out-of-flow descendants of a multi-column container do affect column balancing, 
+	and the block-size of the multi-column container." <a href="https://github.com/w3c/csswg-drafts/issues/6279#issuecomment-839912199">Resolved 12 May 2021</a></li>
+	<li>Added the text, "The margins of two spanners separated only by an absolutely positioned item will collapse with each other, 
 	as absolutely positioned items do not create column boxes." <a href="https://github.com/w3c/csswg-drafts/issues/6265#issuecomment-839909999">Resolved 12 May 2021</a></li>
     <li>Adds an accessibility considerations section. <a href="https://github.com/w3c/csswg-drafts/issues/6283">Request from APA after review.</a></li>
 </ul>
@@ -1557,7 +1562,7 @@ This appendix is <em>informative</em>.
 	</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>
+	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>

css-multicol-1/issues-may-2021.txt

@@ -479,3 +479,10 @@ Summary:  Definition of adjacent spanners, when to create column boxes
 Comments: https://github.com/w3c/csswg-drafts/issues/6265
 Closed:   Accepted
 Resolved: https://github.com/w3c/csswg-drafts/issues/6265#issuecomment-839909999
+----
+Issue 59.
+From:     Morten Stenshorne
+Summary:  Should contained out-of-flow descendants affect column balancing?
+Comments: https://github.com/w3c/csswg-drafts/issues/6279
+Closed:   Accepted
+Resolved: https://github.com/w3c/csswg-drafts/issues/6279#issuecomment-839912199