Fix some bugs

src/layouts/partial-panel-resolver.html

@@ -43,7 +43,7 @@ Polymer({
         hass: this.hass,
         narrow: this.narrow,
         showMenu: this.showMenu,
-        panel: panel,
+        panel: panel.toJS(),
       });
   },
 

src/more-infos/more-info-media_player.html

@@ -38,6 +38,10 @@
       paper-dropdown-menu.source-input {
         margin-left: 10px;
       }
+
+      [hidden] {
+        display: none !important;
+      }
     </style>
 
     <div class$='[[computeClassNames(stateObj)]]'>