• formLimiter: Close your survey automatically, after a maximum number of responses is reached, or at a date and time of your choosing. 
• Ultradox Trigger: Create custom emails, reports, invoices, newsletters, etc., based on information that people enter into your form. 
• Form Values: Store and pull from lists that you use regularly in Forms, like a list of staff, students, rooms, resources or anything you want. 

Earlier this year, we introduced add-ons for Google Docs and Sheets—packaged Apps Script projects that users can easily install from our add-on store to get extra functionality and features.

Since then, plenty of developers told us they were eager to add installable Apps Script triggers to their add-ons. We're happy to announce that now you can do just that, making it possible to respond to more user actions. For example, a spreadsheet add-on can now react when a user submits a response to a Google Form, or can call a method that requires authorization when a user edits a cell.

Add-ons can now programmatically create and manage these installable triggers:

• Sheets add-ons can use the change, edit, open, and form-submit installable triggers.
• Docs add-ons can use the (new!) open installable trigger.

To see the power of installable triggers in action, check out developer Romain Vialard's Yet Another Mail Merge, which has already been updated. The original YAMM lets users quickly personalize Gmail drafts by replacing placeholder fields with data from a spreadsheet. The new version uses a trigger to send an email whenever a form is submitted.

If you've worked with installable triggers before, you'll find that they behave a little differently in add-ons (for one thing, there are no pesky "Summary of failures" emails!), so be sure to check out the documentation.

Posted by Edward Jones, Googler

DocsListDialog is a widget used by only a small fraction of Apps Script projects to provide a Google Drive "file open" dialog in a UI service user interface. In almost all cases, using Google Picker in HTML service is preferable and more secure.

Before September 30, 2014, we require scripts using DocsListDialog to make a small update to improve security.

Specifically, if you use DocsListDialog, you'll need to start calling a new method, setOAuthToken(oAuthToken) before you call showDocsPicker(). The new method sets an OAuth 2.0 token to use when fetching data for the dialog, on behalf of the user whose content should be shown.

So long as the app isn't a web app set to execute as "me" (the developer), you can get the necessary OAuth 2.0 token by calling ScriptApp.getOAuthToken(). The example below shows how to convert an old DocsListDialog implementation to the new model.

Old example

function showDialog() {
  var app = UiApp.createApplication();

  app.createDocsListDialog()
     .addCloseHandler(serverHandler)
     .addSelectionHandler(serverHandler)
     .showDocsPicker();

  SpreadsheetApp.getUi()
     .showModalDialog(app,' ');
}

New example

function showDialog() {
  var app = UiApp.createApplication();

  app.createDocsListDialog()
     .addCloseHandler(serverHandler)
     .addSelectionHandler(serverHandler)
     .setOAuthToken(ScriptApp.getOAuthToken())
     .showDocsPicker();
 
  SpreadsheetApp.getUi()
     .showModalDialog(app,' ');
}

To ensure your script continues to work properly, be sure to make this change before September 30.

Posted by Dan Lazin, Googler