Devtools: Fix disabled element state pane button after reloading

Source/devtools/front_end/elements/StylesSidebarPane.js

Index: Source/devtools/front_end/elements/StylesSidebarPane.js
diff --git a/Source/devtools/front_end/elements/StylesSidebarPane.js b/Source/devtools/front_end/elements/StylesSidebarPane.js
index dcfc44a66357356358747b7576e28ff8fb26e50e..658f4d0b3e1dcffe709d4ec3cf5e26d55e194150 100644
--- a/Source/devtools/front_end/elements/StylesSidebarPane.js
+++ b/Source/devtools/front_end/elements/StylesSidebarPane.js
@@ -42,6 +42,7 @@ WebInspector.StylesSidebarPane = function(requestShowCallback)
 
     var toolbar = new WebInspector.ExtensibleToolbar("styles-sidebarpane-toolbar", this.element);
     toolbar.element.classList.add("styles-pane-toolbar");
+    this._currentToolbarPane = null;
 
     this._requestShowCallback = requestShowCallback;
     var toolbarPaneContainer = this.element.createChild("div", "styles-sidebar-toolbar-pane-container");
@@ -3192,14 +3193,6 @@ WebInspector.StylesSidebarPane.BaseToolbarPaneWidget = function(toolbarItem)
 }
 
 WebInspector.StylesSidebarPane.BaseToolbarPaneWidget.prototype = {
-    /**
-     * @return {!WebInspector.ToolbarItem}
-     */
-    toolbarItem: function()
-    {
-        return this._toolbarItem;
-    },
-
     _nodeChanged: function()
     {
         if (!this.isShowing())