Good catch.
I think this action is OK but there is a problem with the xml for the documentation (actions.xml)
This action actually requires 1 parameter which is a list of the light IDs to store. So for example if you have the starter set with 3 lights you would write the first parameter as
1,2,3
In order to create the field for the parameter (right now there is no box because of the error in the xml) you can either switch the action temporarily to one that requires at least one parameter so that you can enter a value or you can use the parameter helper (blocks icon at the right of the action) and then click + to add an extra param field.