I think there is no option, because there isn't a comment or mute function in the action part. Only in Lua you can.
I have a simple trick: I use an impossible if-clause to activate or disable an action. If I want to test it I set a dummy value or a condition to true (and if neccessary) set another or the same value to false - depends on how many parts you have.
x = 1
if x == 1 then
Setting the value to 0, the action won't start.
OK, it's not very comfortable, but you have only to switch between some values or have to edit a few lines.
I use 4.2.5. No idea, if R5 has a comment or mute option.