Enable/Disable Modification by checking

[caca2331]

When performing different tasks I often need different sets of modifications; since there are many combinations of the tasks, it gets complicated and inefficient to create a profile for each of them. It would be convenient if I can just check to enable/disable a single (or a group of) modification rule, both in simple modification or complex modification mode.
Additionally, this function will also be helpful when testing newly created rules.