[ExecuteInEditMode] only updates when the scene has changed. How do I make a script that runs all the time and not only when things in the scene has changed? It’s just a very small script that changes the intensity of a light (light modulation).
Add a function to the EditorApplication.update, which according to the documentation gets called “approximatelly 100 times per second”.
Generally, it’s best to keep ExecuteInEditMode, then add the function in OnEnable and remove it in OnDisable.