diff --git a/browser/components/customizableui/src/CustomizableUI.jsm b/browser/components/customizableui/src/CustomizableUI.jsm
index 557c3914bfb..995597607eb 100644
--- a/browser/components/customizableui/src/CustomizableUI.jsm
+++ b/browser/components/customizableui/src/CustomizableUI.jsm
@@ -1084,19 +1084,23 @@ let CustomizableUIInternal = {
   /*
    * If people put things in the panel which need more than single-click interaction,
    * we don't want to close it. Right now we check for text inputs and menu buttons.
-   * Anything else we should take care of?
+   * We also check for being outside of any toolbaritem/toolbarbutton, ie on a blank
+   * part of the menu.
    */
   _isOnInteractiveElement: function(aEvent) {
     let target = aEvent.originalTarget;
-    let panel = aEvent.currentTarget;
+    let panel = this._getPanelForNode(aEvent.currentTarget);
     let inInput = false;
     let inMenu = false;
-    while (!inInput && !inMenu && target != aEvent.currentTarget) {
-      inInput = target.localName == "input";
+    let inItem = false;
+    while (!inInput && !inMenu && !inItem && target != panel) {
+      let tagName = target.localName;
+      inInput = tagName == "input";
       inMenu = target.type == "menu";
+      inItem = tagName == "toolbaritem" || tagName == "toolbarbutton";
       target = target.parentNode;
     }
-    return inMenu || inInput;
+    return inMenu || inInput || !inItem;
   },
 
   hidePanelForNode: function(aNode) {