You could set up a test that pops up a message.
Set the action to something that runs as a function from the screen load script... ie the cycle stop function and add a mc.mcCntlSetLastError(inst, "Test Action") to the function and then have your script do the same thing:
local inst = mc.mcGetInstance()
mc.mcCntlSetLastError(inst, "Test Script")
I tried this on my end. I couldn't get a button to do any actions. Weird. I never use the actions, I always add scripts to buttons.
Maybe try this on your end and see what you can do.