In module 6, Using Tables, I'm trying to add an image in the background to a cell.
My problem is that the box with the label 'use background picture' is grayed out in all of the tables I try, including those provided with this module. As a result, I'm not able to change the option by checking it.
It appears that my system has some default option blocking out the insertion of a background image in a cell. How do I trace it?