[css-overflow-3] Margins of flex and grid items are included in scrol…

…lable overflow. #3653

css-overflow-3/Overview.bs

@@ -252,12 +252,20 @@ Scrollable Overflow</h3>
 			and the behavior in the inline axis is <a href="http://jsbin.com/digadoyohi/1/edit?html,css,output">not</a> <a href="http://jsbin.com/vexahocayi/1/edit?html,css,output">clear</a>.
 
 			<!-- Make sure http://jsbin.com/qececaqilo/edit?html,css,output is clearly defined. -->
+
+		<li>
+			the margin areas of <a>grid item</a> and <a>flex item</a> boxes
+			for which the box establishes a containing block.
+			The UA may <em>additionally</em> include
+			the margin areas of other boxes
+			for which the box establishes a containing block;
+			however,
+			the conditions under which such margin areas are included
+			is undefined in this level.
+			<span class="issue">This needs further testing and investigation;
+			is therefore deferred in this draft.</span>
 	</ul>
 
-	The UA may <em>additionally</em> include
-	the margin areas of boxes for which it is the containing block.
-	The conditions under which such margin areas are included is undefined in this level.
-	<span class="issue">This needs further testing and investigation; is therefore deferred in this draft.</span>
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 	Considerations:
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