Add a note.

Author: tabatkins

css-grid/Overview.html

@@ -2291,6 +2291,12 @@ <h3 class="heading settled heading" data-level=8.4 id=abspos-items><span class=s
 		<figure>
 			<img height=402 src=images/abspos-grid.svg width=702>
 		</figure>
+
+<p class=note>		Note: Note that grids and the <a data-link-type=dfn href=#grid-placement-property title="grid-placement properties">grid-placement properties</a> are <a data-link-type=dfn title=flow-relative>flow-relative</a>,
+		while abspos offsets are <a data-link-type=dfn title=physical>physical</a>,
+		so if the <a class=property data-link-type=propdesc href=http://dev.w3.org/csswg/css-writing-modes-3/#propdef-direction title=direction>direction</a> or <a class=property data-link-type=propdesc href=http://dev.w3.org/csswg/css-writing-modes-3/#propdef-writing-mode title=writing-mode>writing-mode</a> properties change,
+		the grid will transform to match,
+		but the offsets won’t.
 	</div>
 
 <h2 class="heading settled heading" data-level=9 id=alignment><span class=secno>9 </span><span class=content>