add missing display size check

Author: josepharhar

source

@@ -56678,7 +56678,8 @@ interface <dfn interface>HTMLSelectElement</dfn> : <span>HTMLElement</span> {
    </li>
 
    <li>
-    <p>If <var>lastSelectedOption</var> is null and <var>firstEnabledOption</var> is not null:</p>
+    <p>If <var>lastSelectedOption</var> is null and <var>firstEnabledOption</var> is not null and
+    <var>element</var>'s <span data-x="concept-select-size">display size</span> is 1:</p>
 
     <ol>
      <li><p>Set <var>firstEnabledOption</var>'s <span