diff --git a/pes-fmdl/CompatibilityLayer.py b/pes-fmdl/CompatibilityLayer.py
index be0f557..ed35493 100644
--- a/pes-fmdl/CompatibilityLayer.py
+++ b/pes-fmdl/CompatibilityLayer.py
@@ -45,7 +45,23 @@ def ExportUVMaps(cls, blenderMaterial, blenderMesh, name, vertexFields):
 	@classmethod
 	def TriangulateMesh(cls, modifiedBlenderMesh, scene):
 		pass
+	
+	@classmethod
+	def AppendToImportMenu(cls, newMenuItem):
+		pass
+	
+	@classmethod
+	def AppendToExportMenu(cls, newMenuItem):
+		pass
+		
+	@classmethod
+	def AppendScenePostUpdateEvent(cls, event):
+		pass
 
+	@classmethod
+	def RemoveSceneUpdatePostEvent(cls, eventHandler):
+		pass
+	
 	def __init__(self):
 		pass
 
@@ -242,9 +258,26 @@ def AppendToImportMenu(cls, newMenuItem):
 	def AppendToExportMenu(cls, newMenuItem):
 		bpy.types.INFO_MT_file_export.append(newMenuItem)
 	
+	@classmethod
+	def AppendScenePostUpdateEvent(cls, eventHandler):
+		bpy.app.handlers.scene_update_post.append(eventHandler)
+		
+	@classmethod
+	def RemoveSceneUpdatePostEvent(cls, eventHandler):
+		bpy.app.handlers.scene_update_post.remove(eventHandler)
+
+	@classmethod
+	def RemoveFromExportMenu(cls, menuItem):
+		bpy.types.INFO_MT_file_export.remove(menuItem)
+
+	@classmethod
+	def RemoveFromImportMenu(cls, menuItem):
+		bpy.types.INFO_MT_file_import.remove(menuItem)
+	
 	def __init__(self):
 		super().__init__()
 
+
 class CompatibilityLayer29(CompatibilityLayerBase):
 
 	@classmethod
@@ -386,6 +419,22 @@ def AppendToImportMenu(cls, newMenuItem):
 	def AppendToExportMenu(cls, newMenuItem):
 		bpy.types.TOPBAR_MT_file_export.append(newMenuItem)
 	
+	@classmethod
+	def AppendSceneUpdatePostEvent(cls, eventHandler):
+		bpy.app.handlers.depsgraph_update_post.append(eventHandler)
+	
+	@classmethod
+	def RemoveSceneUpdatePostEvent(cls, eventHandler):
+		bpy.app.handlers.depsgraph_update_post.remove(eventHandler)
+
+	@classmethod
+	def RemoveFromExportMenu(cls, menuItem):
+		bpy.types.TOPBAR_MT_file_export.remove(menuItem)
+
+	@classmethod
+	def RemoveFromImportMenu(cls, menuItem):
+		bpy.types.TOPBAR_MT_file_import.remove(menuItem)
+
 	def __init__(self):
 		super().__init__()
 
@@ -432,3 +481,15 @@ def AppendToImportMenu(self, newMenuItem):
 	
 	def AppendToExportMenu(self, newMenuItem):
 		self.shim.AppendToExportMenu(newMenuItem)
+	
+	def AppendSceneUpdatePostEvent(self, eventHandler):
+		self.shim.AppendSceneUpdatePostEvent(eventHandler)
+		
+	def RemoveSceneUpdatePostEvent(self, eventHandler):
+		self.shim.RemoveSceneUpdatePostEvent(eventHandler)
+	
+	def RemoveFromExportMenu(self, menuItem):
+		self.shim.RemoveFromExportMenu(menuItem)
+	
+	def RemoveFromImportMenu(self, menuItem):
+		self.shim.RemoveFromImportMenu(menuItem)
diff --git a/pes-fmdl/UI.py b/pes-fmdl/UI.py
index 0280ba3..23386a8 100644
--- a/pes-fmdl/UI.py
+++ b/pes-fmdl/UI.py
@@ -809,14 +809,15 @@ def register():
 	shim.AppendToExportMenu(FMDL_Scene_FMDL_Export_MenuItem)
 	bpy.types.TEXTURE_PT_image.append(FMDL_Texture_Load_Ftex_Button)
 	
-	bpy.app.handlers.scene_update_post.append(FMDL_Mesh_BoneGroup_TrackVertexGroupUsageUpdates)
+	shim.AppendSceneUpdatePostEvent(FMDL_Mesh_BoneGroup_TrackVertexGroupUsageUpdates)
 
 def unregister():
-	bpy.app.handlers.scene_update_post.remove(FMDL_Mesh_BoneGroup_TrackVertexGroupUsageUpdates)
+	shim = CompatibilityLayer.CompatibilityLayer()
+	shim.RemoveSceneUpdatePostEvent(FMDL_Mesh_BoneGroup_TrackVertexGroupUsageUpdates)
 	
 	bpy.types.TEXTURE_PT_image.remove(FMDL_Texture_Load_Ftex_Button)
-	bpy.types.INFO_MT_file_export.remove(FMDL_Scene_FMDL_Export_MenuItem)
-	bpy.types.INFO_MT_file_import.remove(FMDL_Scene_FMDL_Import_MenuItem)
+	shim.RemoveFromExportMenu(FMDL_Scene_FMDL_Export_MenuItem)
+	shim.RemoveFromImportMenu(FMDL_Scene_FMDL_Import_MenuItem)
 	
 	for c in classes[::-1]:
 		bpy.utils.unregister_class(c)