diff --git a/chrome/content/zotero/xpcom/itemTreeView.js b/chrome/content/zotero/xpcom/itemTreeView.js
index efe70bfbdb..55483a87d9 100644
--- a/chrome/content/zotero/xpcom/itemTreeView.js
+++ b/chrome/content/zotero/xpcom/itemTreeView.js
@@ -881,7 +881,7 @@ Zotero.ItemTreeView.prototype.getSortField = function() {
 		return false;
 	}
 	// zotero-items-column-_________
-	return column.substring(20);
+	return column.id.substring(20);
 }