diff --git a/elements/design-canvas/design-canvas.html b/elements/design-canvas/design-canvas.html
index 02993714..0e0dd7c8 100644
--- a/elements/design-canvas/design-canvas.html
+++ b/elements/design-canvas/design-canvas.html
@@ -10,6 +10,7 @@
     :host {
       position: relative;
       outline: none;
+      display: block;
       background-image: url(grid.png);
       -webkit-user-select: none
     }
@@ -70,6 +71,8 @@
   // communication
 
   notifyChange: function() {
+    // force polyfill rendering.
+    this.offsetHeight;
     this.fire('design-change', this);
   },
 
diff --git a/elements/designer-element/designer-element.css b/elements/designer-element/designer-element.css
index 27a5abdd..c2ea0832 100644
--- a/elements/designer-element/designer-element.css
+++ b/elements/designer-element/designer-element.css
@@ -78,6 +78,7 @@ core-icon-button.rotate {
   background-color: #f2f2f2;
   color: #a9a9a9;
   border-bottom: 1px solid #ccc;
+  display: block;
 }
 
 :host /deep/ #tabs > * {