How to create dashboard graph widget that indicates when a configuration change occurred on a device?

I don't have LMConfig (paid add-on) so I'm not sure but that looks like a normal graph widget also showing a Change Detected via an OpsNote-like thing and not a DataSource. The red graph line itself would be a side effect of the change in their example and the actual pop-up message is from the box.

My guess is that you just place a normal graph widget and it will automatically add that dotted line when a change occurs. If that doesn't work, then perhaps look at the graph tab for the device setup with LMConfig then add that to dashboard in case the graph needs specific device setup.