Just a heads up that CutsceneEditor.cs has an issue in the latest 2021.3 LTS. You’ve got a conditional expression related to finding “ToolbarSeachCancelButton”, which it looks like Unity has backported a fix for, so now it’s “ToolbarSearchCancelButton”. This currently spams console warnings any time the Cutscene editor is open.
The workaround, for anyone in the meantime, is to go to CutsceneEditor.cs, and look for the “#if UNITY_2022_3_OR_NEWER”, and change it to “#if UNITY_2021_3_OR_NEWER”.