add a uiwidgetPanel host to StoreConnector, so that we can binding it to the right window.instance when stateChanged callback is triggered

com.unity.uiwidgets/Runtime/redux/widget_redux.cs

 using System;
+using Unity.UIWidgets.editor;
 using Unity.UIWidgets.foundation;
 using Unity.UIWidgets.ui;
 using Unity.UIWidgets.widgets;
 
         public readonly bool pure;
 
+        public readonly UIWidgetsEditorWindow host;
+
+            UIWidgetsEditorWindow host = null,
             ViewModelBuilder<ViewModel> builder = null,
             StoreConverter<State, ViewModel> converter = null,
             bool pure = false, 
             D.assert(converter != null);
+            this.host = host;
             this.pure = pure;
             this.builder = builder;
             this.converter = converter;
                 builder: this.builder,
                 converter: this.converter,
                 pure: this.pure,
-                shouldRebuild: this.shouldRebuild
+                shouldRebuild: this.shouldRebuild,
+                host : this.host
             );
         }
     }
 
         public readonly bool pure;
 
+        public readonly UIWidgetsEditorWindow host;
+
         public _StoreListener(
             ViewModelBuilder<ViewModel> builder = null,
             StoreConverter<State, ViewModel> converter = null,
+            UIWidgetsEditorWindow host = null,
             Key key = null) : base(key) {
             D.assert(builder != null);
             D.assert(converter != null);
             this.converter = converter;
             this.pure = pure;
             this.shouldRebuild = shouldRebuild;
+            this.host = host;
         }
 
         public override widgets.State createState() {
         }
 
         void _handleStateChanged(State state) {
-            if (Window.hasInstance) {
+            if (this.widget.host != null) {
+                var preInstance = Window.instance;
+                using (WindowProvider.of(this.widget.host).getScope()) {
+                    this._innerStateChanged(state);
+                }
+                Window.instance = preInstance;
+            }
+            else if (Window.hasInstance) {
                 this._innerStateChanged(state);
             }
             else {