--- a/browser/components/customizableui/src/CustomizeMode.jsm
+++ b/browser/components/customizableui/src/CustomizeMode.jsm
@@ -332,16 +332,17 @@ CustomizeMode.prototype = {
     }
 
     this._removeExtraToolbarsIfEmpty();
 
     CustomizableUI.removeListener(this);
 
     this.document.removeEventListener("keypress", this);
     this.window.PanelUI.menuButton.removeEventListener("mousedown", this);
+    this.window.PanelUI.menuButton.open = false;
 
     this.window.PanelUI.beginBatchUpdate();
 
     this._removePanelCustomizationPlaceholders();
 
     let window = this.window;
     let document = this.document;
     let documentElement = document.documentElement;
@@ -420,17 +421,16 @@ CustomizeMode.prototype = {
       // And drop all area references.
       this.areas = [];
 
       // Let everybody in this window know that we're starting to
       // exit customization mode.
       CustomizableUI.dispatchToolboxEvent("customizationending", {}, window);
 
       window.PanelUI.setMainView(window.PanelUI.mainView);
-      window.PanelUI.menuButton.open = false;
       window.PanelUI.menuButton.disabled = false;
 
       let customizeButton = document.getElementById("PanelUI-customize");
       customizeButton.setAttribute("exitLabel", customizeButton.getAttribute("label"));
       customizeButton.setAttribute("label", customizeButton.getAttribute("enterLabel"));
       customizeButton.setAttribute("exitTooltiptext", customizeButton.getAttribute("tooltiptext"));
       customizeButton.setAttribute("tooltiptext", customizeButton.getAttribute("enterTooltiptext"));