Sources button in the Output window.
Symptoms/Issue
In the Output window, selecting the Sources button at the top changes the window from showing the values of the fixtures, to where the values are coming from.
Description/Explanation of Issue
For example, if fixtures are on that shouldn't be and it isn't obvious where why they are on, checking the Output window with Sources selected will show the cuelist that is playing and sending the values, List 7, or indicates the values are coming from the Programmer, etc.