diff --git a/python/py_package/utils/viewer/entity_window.py b/python/py_package/utils/viewer/entity_window.py
index 488b2452..b740f933 100644
--- a/python/py_package/utils/viewer/entity_window.py
+++ b/python/py_package/utils/viewer/entity_window.py
@@ -79,7 +79,9 @@ def enable_collision_visual(self, entity=None):
                         vs = sapien.render.RenderShapePlane([1, 1e4, 1e4], blue_mat)
 
                     elif isinstance(s, sapien.physx.PhysxCollisionShapeCylinder):
-                        vs = sapien.render.RenderShapeCylinder(s.radius, s.half_length, green_mat)
+                        vs = sapien.render.RenderShapeCylinder(
+                            s.radius, s.half_length, green_mat
+                        )
 
                     else:
                         raise Exception(
@@ -805,3 +807,6 @@ def get_ui_windows(self):
         if self.ui_window:
             return [self.ui_window]
         return []
+
+    def notify_scene_change(self):
+        self.reset()
diff --git a/python/py_package/utils/viewer/render_window.py b/python/py_package/utils/viewer/render_window.py
index 1f983ad2..d476d7e7 100644
--- a/python/py_package/utils/viewer/render_window.py
+++ b/python/py_package/utils/viewer/render_window.py
@@ -34,6 +34,11 @@ def set_shader(self, index):
 
     def reset(self):
         self.ui_window = None
+        self.shader_dir = None
+        self.shader_index = None
+        self.shader_list = None
+        self.shader_type = None
+        self.shader_types = None
 
     @property
     def is_rt(self):
diff --git a/python/py_package/utils/viewer/transform_window.py b/python/py_package/utils/viewer/transform_window.py
index 57e87b40..07c85fe0 100644
--- a/python/py_package/utils/viewer/transform_window.py
+++ b/python/py_package/utils/viewer/transform_window.py
@@ -14,15 +14,21 @@ def reset(self):
         self.gizmo = None
         self._gizmo_pose = sapien.Pose()
         self.ghost_objects = []
+
         self.ik_articulation = None
-        self.follow = False
         self.ik_enabled = True
-        self.display_ghosts = False
 
-        self.enabled = False
+        self.ik_errpr = None
+        self.ik_result = None
+        self.ik_success = False
 
-        # self.ui_move_group = None
+        self.follow = False
+        self.display_ghosts = False
+        self.enabled = False
+        self.ui_move_group = None
         self.move_group_joints = []
+        self.move_group_selection = []
+        self.pinocchio_model = None
 
     def close(self):
         self.reset()
diff --git a/python/py_package/utils/viewer/viewer.py b/python/py_package/utils/viewer/viewer.py
index 8a1aa062..d7ea280a 100644
--- a/python/py_package/utils/viewer/viewer.py
+++ b/python/py_package/utils/viewer/viewer.py
@@ -53,8 +53,6 @@ def __init__(
         if renderer is None:
             renderer = SapienRenderer()
 
-        self.renderer = renderer
-
         self.renderer_context = renderer._internal_context
 
         if not shader_dir:
@@ -125,7 +123,15 @@ def closed(self):
         return self.window is None
 
     def close(self):
+        for plugin in self.plugins:
+            plugin.close()
+
+        self.selected_entity = None
+        self.scene = None
+        self.system = None
         self.window = None
+        self.plugins = None
+        self.renderer_context = None
 
     def set_camera_pose(self, pose):
         self.window.set_camera_pose(pose)
@@ -140,8 +146,6 @@ def reset_notifications(self):
 
     def render(self):
         if self.window.should_close:
-            for plugin in self.plugins:
-                plugin.close()
             self.close()
 
         if self.closed: