Bug 941990 - The customization context menus don't appear on buttons in the menu panel in customization mode if the panel is not opened prior to entering customization mode. r=Gijs

browser/components/customizableui/content/panelUI.js

@@ -122,7 +122,6 @@ const PanelUI = {
     }
 
     this.ensureReady().then(() => {
-      this.panel.hidden = false;
       let editControlPlacement = CustomizableUI.getPlacementOfWidget("edit-controls");
       if (editControlPlacement && editControlPlacement.area == CustomizableUI.AREA_PANEL) {
         updateEditUIVisibility();
@@ -224,6 +223,7 @@ const PanelUI = {
         CustomizableUI.registerMenuPanel(this.contents);
         this.endBatchUpdate();
       }
+      this.panel.hidden = false;
     }.bind(this)).then(null, Cu.reportError);
 
     return this._readyPromise;