[css-flexbox-1] Make rewrapping of flex column wrap for fragmentation…

… optional. #6855

css-flexbox-1/Overview.bs

@@ -3204,11 +3204,13 @@ Fragmenting Flex Layout</h2>
 			and none of its flex items fit in the remaining space on the page,
 			the entire fragment is moved to the next page.
 
-		<li>
-			When a <a>multi-line</a> column flex container breaks,
-			each fragment has its own "stack" of flex lines,
+<li>
+			When breaking a <a>multi-line</a> column flex container,
+			the UA may organize each fragment into its own “stack” of flex lines--
 			just like each fragment of a multi-column container
-			has its own row of column boxes.
+			has its own row of column boxes--
+			in order to ensure that content presented on earlier pages
+			corresponds to content earlier in the box order.
 
 		<li>
 			Aside from the rearrangement of items imposed by the previous point,
@@ -3769,6 +3771,11 @@ Changes since the <a href="https://www.w3.org/TR/2018/CR-css-flexbox-1-20181119/
 				to resolve where authors expected them to resolve.</ins>
 			</blockquote>
 
+		<li id="change-2018-flex-column-wrap-fragmentation">
+			Made the re-arrangement of [=flex items=] into independent
+			stacks of flex lines on each page optional.
+			(<a href="https://github.com/w3c/csswg-drafts/issues/6855">6855</a>)
+
 		<li id="change-2018-bracket-range-notation">
 			Updated value syntax in property definition tables
 			to use newer <a>CSS bracketed range notation</a>