We have released an update for the Custom HTML add-on! Before, the add-on was overzelous in cleaning your HTML input, causing many add-ons to appear blank when published. The cleaning was good up to a point. It cleaned up your code and helped make sure that if you wrote basic code yourself, it didn't break. However, it wasn't ideal for 3rd party code as it would tend to take out elements that were necessary to publish correctly.
The update works harder to make sure that your code, whether code you've written yourself or found from another website, will work no matter what! Third party code like widgets from widgetbox, Facebook, PayPal, or more work seamlessly.
Once you've submitted your code into the custom HTML module, know that it might not show up in your editor, but once you hit "Publish" you will be able to view it on your live site!