--- a/browser/components/places/content/browserPlacesViews.js
+++ b/browser/components/places/content/browserPlacesViews.js
@@ -1371,17 +1371,17 @@ PlacesToolbar.prototype = {
       return null;
 
     let dropPoint = { ip: null, beforeIndex: null, folderElt: null };
     let elt = aEvent.target;
     if (elt._placesNode && elt != this._rootElt &&
         elt.localName != "menupopup") {
       let eltRect = elt.getBoundingClientRect();
       let eltIndex = Array.indexOf(this._rootElt.childNodes, elt);
-      if (PlacesUIUtils.nodeIsFolder(elt._placesNode) &&
+      if (PlacesUtils.nodeIsFolder(elt._placesNode) &&
           !PlacesUIUtils.isContentsReadOnly(elt._placesNode)) {
         // This is a folder.
         // If we are in the middle of it, drop inside it.
         // Otherwise, drop before it, with regards to RTL mode.
         let threshold = eltRect.width * 0.25;
         if (this.isRTL ? (aEvent.clientX > eltRect.right - threshold)
                        : (aEvent.clientX < eltRect.left + threshold)) {
           // Drop before this folder.