Unity Project

reference
https://cardgames.io/yahtzee/

Library/PackageCache/com.unity.timeline@1.2.15/Editor/Utilities/GUIMixedValueScope.cs

@@ -0,0 +1,20 @@
+using System;
+using UnityEngine;
+
+namespace UnityEditor
+{
+    struct GUIMixedValueScope : IDisposable
+    {
+        readonly bool m_PrevValue;
+        public GUIMixedValueScope(bool newValue)
+        {
+            m_PrevValue = EditorGUI.showMixedValue;
+            EditorGUI.showMixedValue = newValue;
+        }
+
+        public void Dispose()
+        {
+            EditorGUI.showMixedValue = m_PrevValue;
+        }
+    }
+}