Had to go dig it up; it's the indicator use option. You want "any on." If any device in the table is on, the activator device will stay on. This will not tell you which devices are on without going to the app page for the RL instance. If that's really a need for you, you can use this app to create a group that will provide a list of devices that are on. The attribute can be displayed in a dashboard.
Here's a link to the manual, but it does not explicitly explain that option.
@bertabcd1234 there's a section for "advanced use of the indicator" but not a section for standard use. I'm not sure that everyone would be able to infer from the section what it actually does.
