diff --git a/‎test/unit/lazy-upgrade.html‎
Lines changed: 4 additions & 0 deletions b/‎test/unit/lazy-upgrade.html‎
Lines changed: 4 additions & 0 deletions
@@ -43,6 +43,10 @@
 <dom-module id="lazy-child">
   <template>
     <style>
+      /* Work around IE/Edge bug with :not([attr]) */
+      :host([disable-upgrade]) {
+        display: block;
+      }
       :host(:not([disable-upgrade])) {
         display: block;
         border: 2px solid blue;