While editing Lessons and Answers in C3PO, please take note of invisible lists that may be attached to the problem and answer containers.

To remove invisible lists:

1. Go to the Lesson and Answer editor pages
2. Click on each problem/answer container to see if the "Insert Lists" button in the toolbar is selected
3. Remove the invisible list by clicking "Remove Lists"
4. Repeat these steps until there are no more invisible lists