In "ObjectEditor.cs" just replace `public override void OnInspectorGUI() { DrawDefaultInspector(); _buttonsDrawer.DrawButtons(targets); } ` with public override VisualElement CreateInspectorGUI() { VisualElement container = new VisualElement(); InspectorElement.FillDefaultInspector(container, serializedObject, this); IMGUIContainer iMGUIContainer = new IMGUIContainer(() => { _buttonsDrawer.DrawButtons(targets); }); container.Add(iMGUIContainer); return container; } It's just more performant in the Editor.