diff --git a/hassio/src/hassio-app.js b/hassio/src/hassio-app.js
deleted file mode 100644
index a39072e583..0000000000
--- a/hassio/src/hassio-app.js
+++ /dev/null
@@ -1,41 +0,0 @@
-import { html } from "@polymer/polymer/lib/utils/html-tag";
-import { PolymerElement } from "@polymer/polymer/polymer-element";
-
-import "./hassio-main";
-import "./resources/hassio-icons";
-
-class HassioApp extends PolymerElement {
-  static get template() {
-    return html`
-      <template is="dom-if" if="[[hass]]">
-        <hassio-main hass="[[hass]]" route="[[route]]"></hassio-main>
-      </template>
-    `;
-  }
-
-  static get properties() {
-    return {
-      hass: Object,
-      route: Object,
-      hassioPanel: {
-        type: Object,
-        value: window.parent.hassioPanel,
-      },
-    };
-  }
-
-  ready() {
-    super.ready();
-    window.setProperties = this.setProperties.bind(this);
-    this.addEventListener("location-changed", () => this._locationChanged());
-    this.addEventListener("hass-toggle-menu", (ev) =>
-      this.hassioPanel.fire("hass-toggle-menu", ev.detail)
-    );
-  }
-
-  _locationChanged() {
-    this.hassioPanel.navigate(window.location.pathname);
-  }
-}
-
-customElements.define("hassio-app", HassioApp);
diff --git a/hassio/src/hassio-main.js b/hassio/src/hassio-main.js
index 8b207f9a00..84fbbc5383 100644
--- a/hassio/src/hassio-main.js
+++ b/hassio/src/hassio-main.js
@@ -79,6 +79,17 @@ class HassioMain extends EventsMixin(NavigateMixin(PolymerElement)) {
     super.ready();
     applyThemesOnElement(this, this.hass.themes, this.hass.selectedTheme, true);
     this.addEventListener("hass-api-called", (ev) => this.apiCalled(ev));
+    // Paulus - March 17, 2019
+    // We went to a single hass-toggle-menu event in HA 0.90. However, the
+    // supervisor UI can also run under older versions of Home Assistant.
+    // So here we are going to translate toggle events into the appropriate
+    // open and close events. These events are a no-op in newer versions of
+    // Home Assistant.
+    this.addEventListener("hass-toggle-menu", () => {
+      window.parent.customPanel.fire(
+        this.hass.dockedSidebar ? "hass-close-menu" : "hass-open-menu"
+      );
+    });
   }
 
   connectedCallback() {