"Stop" trigger does not work.....

It seems to be a pretty simple procedure:

Click the trigger icon at the desired place in the timeline, then click the "Stop" button in the code panel to add the code. I don't add anything to the  code. I just want a simple "stop".

I must be missing something. Because it doesn't work. I have reinstalled and deleted the old preferences. Still doesn't work.

Any and all help would be appreciated.