--- a/browser/modules/BrowserUITelemetry.jsm
+++ b/browser/modules/BrowserUITelemetry.jsm
@@ -530,17 +530,17 @@ this.BrowserUITelemetry = {
       }
     }
 
     // Now go through the items in the palette to see what default
     // items are in there.
     let paletteItems =
       CustomizableUI.getUnusedWidgets(aWindow.gNavToolbox.palette);
     let defaultRemoved = [];
-    for (item of paletteItems) {
+    for (let item of paletteItems) {
       if (DEFAULT_ITEMS.indexOf(item.id) != -1) {
         defaultRemoved.push(item.id);
       }
     }
 
     result.defaultKept = defaultKept;
     result.defaultMoved = defaultMoved;
     result.nondefaultAdded = nondefaultAdded;