Hey there. I may have an answer to your question.
There are really 2 ways to resolve this issue.
One completely removes the lighting function from Showtime event, or any event. This is kind of an ugly hack.
The other will allow you to further customize what it does, when the Showtime event is fired.
To start either way, to modify how an event is responded to, go to:
Advanced > Configuration > Scenarios from the top of the webadmin:
Then in the left hand column, you will see a list of nested scenarios, the one you want to expand is:
"Scenarios for Event Handlers" and then click the "Watching: <insert room here>"
*** See image below ***
After that the window on the right will show you:
*** See image below ***
Here in this image we see it executes command 245, which is the auto-generated Showtime scenario for my Living Room.
You can either delete this command - Kinda hacky, but possibly not. Or you can modify that scenario by scrolling up in the current left pane, to "Lighting Scenarios" and modify the existing scenario.
Or, you can create a whole new lighting scenario. I did this option, because I wanted to create a lighting scenario that would only fire at NIGHT.
After creating this new scenario, I just changed the number in the "Watching - Living Room, Living Room" scenario, and then I made another one to do nothing with the lights, for use in DAY scenarios. I did this for both "Watching - Living Room, Living Room" and "Not Watching - Living Room, Living Room"
If you play with the scenarios and the call functions, you can do all kinds of crazy stuff.
But the short answer is option One. Either delete the command group from the "Watching - <insert room here>", or modify directly the appropriate Lighting Scenario from the same portion of the web admin page.
Hope this helps. I intend on doing a Wiki entry for advanced scenarios, while on Holidays next two weeks.
Best Regards,
Seth