Why am I not able to save a Functional Setup Manager task page to my favorites list?

Probably, you have opened the task using the Setup and Maintenance work area.

To mark a Functional Setup Manager task page as favorite, as a one-time process, open the task using the Offerings work area. After you mark a task as favorite, you can access it directly from the Favorites and Recent Items list.

1. Click Navigator > My Enterprise > Offerings.
2. On the Offerings page, select the offering you want to implement.
3. Click Opt In Features.
4. Click on the Setup icon for the required feature or functional area.
5. Search for and open the task.
6. On the task page, click the Favorites and Recent Items icon to add the page to your favorites list.