diff --git a/old_nodes/__init__.py b/old_nodes/__init__.py
index aeb0ce3eb3..cfb985a510 100644
--- a/old_nodes/__init__.py
+++ b/old_nodes/__init__.py
@@ -106,17 +106,22 @@ def has_old_nodes(tree) -> bool:
 
 def register_old(bl_id):
     """Register old node class"""
-    if bl_id in old_bl_idnames:
-        mod = importlib.import_module(".{}".format(old_bl_idnames[bl_id]), __name__)
-        res = inspect.getmembers(mod)
-        for name, cls in res:
-            if inspect.isclass(cls):
-                if issubclass(cls, bpy.types.Node) and cls.bl_idname == bl_id:
-                    if bl_id not in imported_mods:
-                        mod.register()
-                        imported_mods[bl_id] = mod
-    else:
+    if bl_id in imported_mods:
+        return
+    if bl_id not in old_bl_idnames:
         raise LookupError(f"Cannot find {bl_id} among old nodes")
+    mod = importlib.import_module(".{}".format(old_bl_idnames[bl_id]), __name__)
+    res = inspect.getmembers(mod)
+    module_node_bl_idnames = set()  # there can be multiple of them
+    for name, cls in res:
+        if inspect.isclass(cls):
+            if issubclass(cls, bpy.types.Node):
+                module_node_bl_idnames.add(cls.bl_idname)
+    if bl_id not in module_node_bl_idnames:
+        raise LookupError(f"Old_bl_idnames returns something wrong for {bl_id=}")
+    mod.register()
+    for bl_idname in module_node_bl_idnames:
+        imported_mods[bl_idname] = mod
 
 
 def register_all():
diff --git a/tests/group_tests.py b/tests/group_tests.py
index 1d37078704..9d9a97c533 100644
--- a/tests/group_tests.py
+++ b/tests/group_tests.py
@@ -24,7 +24,7 @@ def test_grouping_nodes(self):
                 importer.import_into_tree(new_tree, print_log=False)
                 [setattr(n, 'select', False) for n in new_tree.nodes]
                 [setattr(new_tree.nodes[n], 'select', True) for n in ['A Number', 'Formula',
-                                                                      'Vector polar input', 'Vector polar output']]
+                                                                      'Vector Polar Input', 'Vector Polar Output']]
                 with self.subTest(msg="Grouping nodes"):
                     bpy.ops.node.add_group_tree_from_selected()
                 with self.subTest(msg="Ungrouping nodes"):
diff --git a/ui/testing_panel.py b/ui/testing_panel.py
index 084109c255..f9c6ea1357 100644
--- a/ui/testing_panel.py
+++ b/ui/testing_panel.py
@@ -37,7 +37,7 @@ def execute(self, context):
             # making self.report after all tests lead to strange error, so no report for testing all
             test.run_all_tests()
         else:
-            test_result = test.run_test_from_file(self.test_module + '.py')
+            test_result = test.run_all_tests(self.test_module + '.py')
             self.report(type={'ERROR'} if test_result != 'OK' else {'INFO'}, message=test_result)
         return {'FINISHED'}
 
diff --git a/utils/sv_json_struct.py b/utils/sv_json_struct.py
index 3df84baae3..8deab77645 100644
--- a/utils/sv_json_struct.py
+++ b/utils/sv_json_struct.py
@@ -648,19 +648,21 @@ def build(self, node, factories: StructFactory, imported_data: OldNewNames):
         # it will cause replacing of all sockets with wrong identifiers in the group node.
         # clearing and adding sockets of Group input and Group output nodes
         # immediately cause their rebuilding by Blender, so JSON file does not save information about their sockets.
-        if node.bl_idname not in {'NodeGroupInput', 'NodeGroupOutput'}:
+        build_in_id_names = {
+            'NodeGroupInput', 'NodeGroupOutput', 'NodeFrame', 'NodeReroute'}
+        if node.bl_idname not in build_in_id_names:
             node.inputs.clear()
-        for sock_identifier, raw_struct in self._struct.get("inputs", dict()).items():
-            with self.logger.add_fail("Add in socket",
-                                      f"Tree: {node.id_data.name}, Node {node.name}, Sock: {sock_identifier}"):
-                factories.sock(sock_identifier, self.logger, raw_struct).build(node.inputs, factories, imported_data)
+            for sock_identifier, raw_struct in self._struct.get("inputs", dict()).items():
+                with self.logger.add_fail("Add in socket",
+                                          f"Tree: {node.id_data.name}, Node {node.name}, Sock: {sock_identifier}"):
+                    factories.sock(sock_identifier, self.logger, raw_struct).build(node.inputs, factories, imported_data)
 
-        if node.bl_idname not in {'NodeGroupInput', 'NodeGroupOutput'}:
+        if node.bl_idname not in build_in_id_names:
             node.outputs.clear()
-        for sock_identifier, raw_struct in self._struct.get("outputs", dict()).items():
-            with self.logger.add_fail("Add out socket",
-                                      f"Tree: {node.id_data.name}, Node {node.name}, Sock: {sock_identifier}"):
-                factories.sock(sock_identifier, self.logger, raw_struct).build(node.outputs, factories, imported_data)
+            for sock_identifier, raw_struct in self._struct.get("outputs", dict()).items():
+                with self.logger.add_fail("Add out socket",
+                                          f"Tree: {node.id_data.name}, Node {node.name}, Sock: {sock_identifier}"):
+                    factories.sock(sock_identifier, self.logger, raw_struct).build(node.outputs, factories, imported_data)
 
         if hasattr(node, 'load_from_json'):
             with self.logger.add_fail("Setting advance node properties",