Fix

Runtime/editor/editor_window.cs

                 this.flushMicrotasks();
             }
         }
-
+        
+        static readonly TimeSpan _coolDownDelay = new TimeSpan(0, 0, 0, 0, 200);
+        static Timer frameCoolDownTimer;
+        
-            doSpeedUp();
-            doCoolDown();
+            onFrameRateSpeedUp();
+            frameCoolDownTimer?.cancel();
+            frameCoolDownTimer = instance.run(
+                _coolDownDelay,
+                () => {
+                    onFrameRateCoolDown();
+                    frameCoolDownTimer = null;
+                });
         }
 
         public override void render(Scene scene) {
                 };
                 this._binding.renderView?.visitChildren(visitor);
             }
-        }
-
-        static Timer scheduleFrameTimer;
-
-        static void doSpeedUp() {
-            onFrameRateSpeedUp();
-        }
-
-        static void doCoolDown() {
-            scheduleFrameTimer?.cancel();
-            scheduleFrameTimer = instance.run(
-                new TimeSpan(0, 0, 0, 0, 200),
-                () => {
-                    onFrameRateCoolDown();
-                    scheduleFrameTimer = null;
-                });
         }
     }
 }

Runtime/ui/window.cs

         public const int defaultMaxTargetFrameRate = 60;
         public const int defaultMinTargetFrameRate = 15;
 
-        static Action _onFrameRateSpeedUp = defaultFrateRateSpeedUp;
+        static Action _onFrameRateSpeedUp = defaultFrameRateSpeedUp;
-                    _onFrameRateSpeedUp = defaultFrateRateSpeedUp;
+                    _onFrameRateSpeedUp = defaultFrameRateSpeedUp;
                 }
                 else {
                     _onFrameRateSpeedUp = value;
 
-        static void defaultFrateRateSpeedUp() {
+        static void defaultFrameRateSpeedUp() {
-        static Action _onFrameRateCoolDown = defaultFrateRateCoolDown;
+        static Action _onFrameRateCoolDown = defaultFrameRateCoolDown;
-                    _onFrameRateCoolDown = defaultFrateRateCoolDown;
+                    _onFrameRateCoolDown = defaultFrameRateCoolDown;
                 }
                 else {
                     _onFrameRateCoolDown = value;
 
-        static void defaultFrateRateCoolDown() {
+        static void defaultFrameRateCoolDown() {
             Application.targetFrameRate = defaultMinTargetFrameRate;
         }
     }