diff --git a/light9/web/lib/bower.json b/light9/web/lib/bower.json
--- a/light9/web/lib/bower.json
+++ b/light9/web/lib/bower.json
@@ -29,7 +29,8 @@
     "polymer": "Polymer/polymer#^2.0.0",
     "iron-flex-layout": "PolymerElements/iron-flex-layout#^2.0.3",
     "iron-component-page": "PolymerElements/iron-component-page#^3.0.1",
-    "paper-header-panel": "PolymerElements/paper-header-panel#^2.1.0"
+    "paper-header-panel": "PolymerElements/paper-header-panel#^2.1.0",
+    "iron-overlay-behavior": "PolymerElements/iron-overlay-behavior#^2.3.4"
   },
   "resolutions": {
     "webcomponentsjs": "^v1.1.0",
@@ -38,6 +39,7 @@
     "paper-button": "^2.1.1",
     "iron-component-page": "^3.0.1",
     "iron-doc-viewer": "^3.0.0",
-    "paper-header-panel": "^2.1.0"
+    "paper-header-panel": "^2.1.0",
+    "iron-overlay-behavior": "^2.3.4"
   }
 }