This demo illustrates the fact that clicking on a green element can lead to additional green elements. In the initial state here, row c is not green since it does not need to be changed to reach a minimal repair state. However, if row f is removed, then row c becomes green as there is now a new minimal repair possible.
Open the table rules and examine . Note that they are closed under resolution and subsumption. Now, hld down teh option key and observe that all rows are green except for a (which is not involved in any constraints) and c (which is not part of any minimal repair). Now, remove f. Hold down the option key again and note that c is now green.