Checklist for adding code to Lessons:

• All strings must be internationalized
• All code must be accessible. Includes any libraries used
• All added code must check for necessary permissions
• POSTs must send and check the CSRF token
• Any new items must implement restrictions: "this item is required" and "this item must not be shown until prerequisites have been met". In a few cases, e.g. inline content, there's no way to check whether someone has done the item. In that case "required" won't be implemented, but it still won't be shown until prerequisites have been met.
• It must be possible to restrict access to an item by group
• The author's UI must show if an item is restricted to groups or if it is unavailable, e.g. because the underlying object hasn't been released, etc. That's normally done by a message in brackets after the title.
• Make sure you verify that you can add the item using the add content icon at the top (which adds it at the end of the page) and also the + icons in the middle of the page (which adds it above a current item)
• Make sure the item shows properly in the reorder screen and in the index of pages if display of individual items is enabled
• Make sure the style in which the item is shown matches the rest of Lessons. Where possible inherit styles from Morpheus, particularly for colors.
• Check markup for all screen widths. Check also when a Lessons tool is the second tool on a page. (An Admin will have to edit the page to do that.) Note that layout at the top is slightly different when it's the second tool, because there's no way lessons can change the header for the tool.

For new code I encourage doing something that isn't in the original code but should have been:

• The popups used to create an item and to edit an existing item should be the same. That way all options can be set when creating an item.

If anyone has time, I'd love to see the existing popups fixed to be that way.