Add Play Scene Tool

Assets/DefaultParentForEditor.cs

@@ -0,0 +1,45 @@
+#if UNITY_EDITOR
+using UnityEditor;
+#endif
+
+using UnityEngine;
+
+namespace Chameleon
+{
+    [ExecuteAlways]
+    [AddComponentMenu("Tools/Chameleon/Default Parent (Editor)")]
+    public class DefaultParentForEditor : MonoBehaviour
+    {
+#if UNITY_EDITOR
+        static DefaultParentForEditor selection;
+
+        [RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.SubsystemRegistration)]
+        static void Init() => selection = null;
+
+        void Update()
+        {
+            if (Application.isPlaying)
+                return;
+
+            var activeGameObject = Selection.activeGameObject;
+            if (activeGameObject != gameObject)
+                return;
+
+            if (!activeGameObject.TryGetComponent(out DefaultParentForEditor defaultParent))
+                return;
+
+            if (selection && selection != defaultParent)
+            {
+                selection = null;
+                EditorUtility.ClearDefaultParentObject();
+            }
+
+            if (!selection)
+            {
+                selection = this;
+                EditorUtility.SetDefaultParentObject(gameObject);
+            }
+        }
+#endif
+    }
+}