--- a/browser/components/customizableui/CustomizeMode.jsm
+++ b/browser/components/customizableui/CustomizeMode.jsm
@@ -579,17 +579,22 @@ CustomizeMode.prototype = {
   },
 
   addToToolbar(aNode) {
     aNode = this._getCustomizableChildForNode(aNode);
     if (aNode.localName == "toolbarpaletteitem" && aNode.firstChild) {
       aNode = aNode.firstChild;
     }
 
-    CustomizableUI.addWidgetToArea(aNode.id, CustomizableUI.AREA_NAVBAR);
+    let widgetToAdd = aNode.id;
+    if (CustomizableUI.isSpecialWidget(widgetToAdd) && aNode.closest("#customization-palette")) {
+      widgetToAdd = widgetToAdd.match(/^customizableui-special-(spring|spacer|separator)/)[1];
+    }
+
+    CustomizableUI.addWidgetToArea(widgetToAdd, CustomizableUI.AREA_NAVBAR);
     if (!this._customizing) {
       CustomizableUI.dispatchToolboxEvent("customizationchange");
     }
 
     // If the user explicitly moves this item, turn off autohide.
     if (aNode.id == "downloads-button") {
       Services.prefs.setBoolPref(kDownloadAutoHidePref, false);
       if (this._customizing) {