Set a max limit on extension items' labels in context menus....

chrome/test/data/extensions/context_menus/long_title/test.js

+// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+window.onload = function() {
+  // Make a 1000-character long title.
+  var title = "";
+  for (var i = 0; i < 1000; i++) {
+    title += "x";
+  }
+  chrome.test.log("creating item");
+  chrome.contextMenus.create({"title":title}, function() {
+    if (!chrome.extension.lastError) {
+      chrome.test.sendMessage("created");
+    }
+  });
+};