Identifying missing add-ons

If you open a page in a .notebook file that requires an add-on that isn’t installed or is disabled on your computer, a message appears at the top of the page. Press the message to open the Add-on Manager. The Add-on Manager identifies which add-on is required. You can then install that add-on (see  Installing add-ons) or enable it (see Disabling and removing add-ons).