[css-grid-1] Clarify that you only look for baseline-aligned items that are aligned *to the correct baseline*. Fixes #5293.

Author: tabatkins

css-grid-1/Overview.bs

@@ -3643,7 +3643,7 @@ Grid Container Baselines</h3>
 			containing at least one [=grid item=].
 
 			If any of the [=grid items=] intersecting this row
-			participate in [=baseline alignment=],
+			participate in [=baseline alignment=] in that row,
 			the grid container's <a>baseline set</a>
 			is <a lt="generate baselines">generated</a> from
 			the shared <a>alignment baseline</a> of those <a>grid items</a>.
@@ -4962,6 +4962,19 @@ Minor Changes</h4>
 						according to the rules of its <a>alignment context</a>.
 				</ol>
 			</blockquote>
+
+		<li id="change-2017-need-correct-baseline-align">
+			Properly limit the item search to just
+			the items participating <em>in the correct baseline alignment</em>.
+			(<a href="https://github.com/w3c/csswg-drafts/issues/5293">Issue 5293</a>)
+
+			<blockquote>
+				If any of the [=grid items=] intersecting this row
+				participate in [=baseline alignment=] <ins>in that row</ins>,
+				the grid container's <a>baseline set</a>
+				is <a lt="generate baselines">generated</a> from
+				the shared <a>alignment baseline</a> of those <a>grid items</a>.
+			</blockquote>
 	</ul>
 
 <h4 id="clarify-2017">