diff --git a/rsconcept/backend/apps/oss/models/OperationSchema.py b/rsconcept/backend/apps/oss/models/OperationSchema.py
index 39eeae94..f10219e7 100644
--- a/rsconcept/backend/apps/oss/models/OperationSchema.py
+++ b/rsconcept/backend/apps/oss/models/OperationSchema.py
@@ -95,14 +95,15 @@ class OperationSchema:
         self.save(update_fields=['time_update'])
         return result
 
-    def delete_operation(self, target: Operation, keep_constituents: bool = False):
+    def delete_operation(self, target: int, keep_constituents: bool = False):
         ''' Delete operation. '''
+        operation = self.cache.operation_by_id[target]
         if not keep_constituents:
-            schema = self.cache.get_schema(target)
+            schema = self.cache.get_schema(operation)
             if schema is not None:
-                self.before_delete_cst(schema.cache.constituents, schema)
-        self.cache.remove_operation(target.pk)
-        target.delete()
+                self.before_delete_cst(schema, schema.cache.constituents)
+        self.cache.remove_operation(target)
+        operation.delete()
         self.save(update_fields=['time_update'])
 
     def set_input(self, target: int, schema: Optional[LibraryItem]) -> None:
@@ -115,7 +116,7 @@ class OperationSchema:
 
         if old_schema is not None:
             if has_children:
-                self.before_delete_cst(old_schema.cache.constituents, old_schema)
+                self.before_delete_cst(old_schema, old_schema.cache.constituents)
             self.cache.remove_schema(old_schema)
 
         operation.result = schema
@@ -128,59 +129,76 @@ class OperationSchema:
 
         if schema is not None and has_children:
             rsform = RSForm(schema)
-            self.after_create_cst(list(rsform.constituents()), rsform)
+            self.after_create_cst(rsform, list(rsform.constituents()))
         self.save(update_fields=['time_update'])
 
-    def set_arguments(self, operation: Operation, arguments: list[Operation]) -> None:
+    def set_arguments(self, target: int, arguments: list[Operation]) -> None:
         ''' Set arguments to operation. '''
+        self.cache.ensure_loaded()
+        operation = self.cache.operation_by_id[target]
         processed: list[Operation] = []
-        changed = False
+        deleted: list[Argument] = []
         for current in operation.getArguments():
             if current.argument not in arguments:
-                changed = True
-                current.delete()
+                deleted.append(current)
             else:
                 processed.append(current.argument)
+        if len(deleted) > 0:
+            self.before_delete_arguments(operation, [x.argument for x in deleted])
+            for deleted_arg in deleted:
+                self.cache.remove_argument(deleted_arg)
+            Argument.objects.filter(pk__in=[x.pk for x in deleted]).delete()
+
+        added: list[Operation] = []
         for arg in arguments:
             if arg not in processed:
-                changed = True
                 processed.append(arg)
-                Argument.objects.create(operation=operation, argument=arg)
-        if not changed:
-            return
-        # TODO: trigger on_change effects
-        self.save(update_fields=['time_update'])
+                new_arg = Argument.objects.create(operation=operation, argument=arg)
+                self.cache.insert_argument(new_arg)
+                added.append(arg)
+        if len(added) > 0:
+            self.after_create_arguments(operation, added)
+        if len(added) > 0 or len(deleted) > 0:
+            self.save(update_fields=['time_update'])
 
-    def set_substitutions(self, target: Operation, substitutes: list[dict]) -> None:
+    def set_substitutions(self, target: int, substitutes: list[dict]) -> None:
         ''' Clear all arguments for operation. '''
+        self.cache.ensure_loaded()
+        operation = self.cache.operation_by_id[target]
+        schema = self.cache.get_schema(operation)
         processed: list[dict] = []
-        changed = False
-
-        for current in target.getSubstitutions():
+        deleted: list[Substitution] = []
+        for current in operation.getSubstitutions():
             subs = [
                 x for x in substitutes
                 if x['original'] == current.original and x['substitution'] == current.substitution
             ]
             if len(subs) == 0:
-                changed = True
-                current.delete()
+                deleted.append(current)
             else:
                 processed.append(subs[0])
+        if len(deleted) > 0:
+            if schema is not None:
+                for sub in deleted:
+                    self._undo_substitution(schema, sub)
+            else:
+                for sub in deleted:
+                    self.cache.remove_substitution(sub)
+                Substitution.objects.filter(pk__in=[x.pk for x in deleted]).delete()
 
-        for sub in substitutes:
-            if sub not in processed:
-                changed = True
-                Substitution.objects.create(
-                    operation=target,
-                    original=sub['original'],
-                    substitution=sub['substitution']
+        added: list[Substitution] = []
+        for sub_item in substitutes:
+            if sub_item not in processed:
+                new_sub = Substitution.objects.create(
+                    operation=operation,
+                    original=sub_item['original'],
+                    substitution=sub_item['substitution']
                 )
+                added.append(new_sub)
+        self._process_added_substitutions(schema, added)
 
-        if not changed:
-            return
-        # TODO: trigger on_change effects
-
-        self.save(update_fields=['time_update'])
+        if len(added) > 0 or len(deleted) > 0:
+            self.save(update_fields=['time_update'])
 
     def create_input(self, operation: Operation) -> RSForm:
         ''' Create input RSForm. '''
@@ -240,9 +258,9 @@ class OperationSchema:
         self.save(update_fields=['time_update'])
         return True
 
-    def after_create_cst(self, cst_list: list[Constituenta], source: RSForm) -> None:
+    def after_create_cst(self, source: RSForm, cst_list: list[Constituenta]) -> None:
         ''' Trigger cascade resolutions when new constituent is created. '''
-        self.cache.insert(source)
+        self.cache.insert_schema(source)
         inserted_aliases = [cst.alias for cst in cst_list]
         depend_aliases: set[str] = set()
         for new_cst in cst_list:
@@ -254,17 +272,17 @@ class OperationSchema:
             if cst is not None:
                 alias_mapping[alias] = cst
         operation = self.cache.get_operation(source.model.pk)
-        self._cascade_create_cst(cst_list, operation, alias_mapping)
+        self._cascade_inherit_cst(operation.pk, source, cst_list, alias_mapping)
 
-    def after_change_cst_type(self, target: Constituenta, source: RSForm) -> None:
+    def after_change_cst_type(self, source: RSForm, target: Constituenta) -> None:
         ''' Trigger cascade resolutions when constituenta type is changed. '''
-        self.cache.insert(source)
+        self.cache.insert_schema(source)
         operation = self.cache.get_operation(source.model.pk)
-        self._cascade_change_cst_type(target.pk, target.cst_type, operation.pk)
+        self._cascade_change_cst_type(operation.pk, target.pk, target.cst_type)
 
-    def after_update_cst(self, target: Constituenta, data: dict, old_data: dict, source: RSForm) -> None:
+    def after_update_cst(self, source: RSForm, target: Constituenta, data: dict, old_data: dict) -> None:
         ''' Trigger cascade resolutions when constituenta data is changed. '''
-        self.cache.insert(source)
+        self.cache.insert_schema(source)
         operation = self.cache.get_operation(source.model.pk)
         depend_aliases = self._extract_data_references(data, old_data)
         alias_mapping: CstMapping = {}
@@ -273,56 +291,94 @@ class OperationSchema:
             if cst is not None:
                 alias_mapping[alias] = cst
         self._cascade_update_cst(
-            cst_id=target.pk,
             operation=operation.pk,
+            cst_id=target.pk,
             data=data,
             old_data=old_data,
             mapping=alias_mapping
         )
 
-    def before_delete_cst(self, target: list[Constituenta], source: RSForm) -> None:
+    def before_delete_cst(self, source: RSForm, target: list[Constituenta]) -> None:
         ''' Trigger cascade resolutions before constituents are deleted. '''
-        self.cache.insert(source)
+        self.cache.insert_schema(source)
         operation = self.cache.get_operation(source.model.pk)
-        self._cascade_before_delete(target, operation.pk)
+        self._cascade_delete_inherited(operation.pk, target)
 
-    def before_substitute(self, substitutions: CstSubstitution, source: RSForm) -> None:
+    def before_substitute(self, source: RSForm, substitutions: CstSubstitution) -> None:
         ''' Trigger cascade resolutions before constituents are substituted. '''
-        self.cache.insert(source)
+        self.cache.insert_schema(source)
         operation = self.cache.get_operation(source.model.pk)
         self._cascade_before_substitute(substitutions, operation)
 
-    def _cascade_create_cst(self, cst_list: list[Constituenta], operation: Operation, mapping: CstMapping) -> None:
-        children = self.cache.graph.outputs[operation.pk]
+    def before_delete_arguments(self, target: Operation, arguments: list[Operation]) -> None:
+        ''' Trigger cascade resolutions before arguments are deleted. '''
+        if target.result_id is None:
+            return
+        for argument in arguments:
+            parent_schema = self.cache.get_schema(argument)
+            if parent_schema is not None:
+                self._execute_delete_inherited(target.pk, parent_schema.cache.constituents)
+
+    def after_create_arguments(self, target: Operation, arguments: list[Operation]) -> None:
+        ''' Trigger cascade resolutions after arguments are created. '''
+        schema = self.cache.get_schema(target)
+        if schema is None:
+            return
+        for argument in arguments:
+            parent_schema = self.cache.get_schema(argument)
+            if parent_schema is None:
+                continue
+            self._execute_inherit_cst(
+                target_operation=target.pk,
+                source=parent_schema,
+                items=list(parent_schema.constituents()),
+                mapping={}
+            )
+
+    def _cascade_inherit_cst(
+        self,
+        target_operation: int,
+        source: RSForm,
+        items: list[Constituenta],
+        mapping: CstMapping
+    ) -> None:
+        children = self.cache.graph.outputs[target_operation]
         if len(children) == 0:
             return
-        source_schema = self.cache.get_schema(operation)
-        assert source_schema is not None
         for child_id in children:
-            child_operation = self.cache.operation_by_id[child_id]
-            child_schema = self.cache.get_schema(child_operation)
-            if child_schema is None:
-                continue
+            self._execute_inherit_cst(child_id, source, items, mapping)
 
-            # TODO: update substitutions for diamond synthesis (if needed)
+    def _execute_inherit_cst(
+        self,
+        target_operation: int,
+        source: RSForm,
+        items: list[Constituenta],
+        mapping: CstMapping
+    ) -> None:
+        operation = self.cache.operation_by_id[target_operation]
+        destination = self.cache.get_schema(operation)
+        if destination is None:
+            return
 
-            self.cache.ensure_loaded()
-            new_mapping = self._transform_mapping(mapping, child_operation, child_schema)
-            alias_mapping = OperationSchema._produce_alias_mapping(new_mapping)
-            insert_where = self._determine_insert_position(cst_list[0], child_operation, source_schema, child_schema)
-            new_cst_list = child_schema.insert_copy(cst_list, insert_where, alias_mapping)
-            for index, cst in enumerate(new_cst_list):
-                new_inheritance = Inheritance.objects.create(
-                    operation=child_operation,
-                    child=cst,
-                    parent=cst_list[index]
-                )
-                self.cache.insert_inheritance(new_inheritance)
-            new_mapping = {alias_mapping[alias]: cst for alias, cst in new_mapping.items()}
-            self._cascade_create_cst(new_cst_list, child_operation, new_mapping)
+        # TODO: update substitutions for diamond synthesis (if needed)
 
-    def _cascade_change_cst_type(self, cst_id: int, ctype: CstType, operation: int) -> None:
-        children = self.cache.graph.outputs[operation]
+        self.cache.ensure_loaded()
+        new_mapping = self._transform_mapping(mapping, operation, destination)
+        alias_mapping = OperationSchema._produce_alias_mapping(new_mapping)
+        insert_where = self._determine_insert_position(items[0], operation, source, destination)
+        new_cst_list = destination.insert_copy(items, insert_where, alias_mapping)
+        for index, cst in enumerate(new_cst_list):
+            new_inheritance = Inheritance.objects.create(
+                operation=operation,
+                child=cst,
+                parent=items[index]
+            )
+            self.cache.insert_inheritance(new_inheritance)
+        new_mapping = {alias_mapping[alias]: cst for alias, cst in new_mapping.items()}
+        self._cascade_inherit_cst(operation.pk, destination, new_cst_list, new_mapping)
+
+    def _cascade_change_cst_type(self, operation_id: int, cst_id: int, ctype: CstType) -> None:
+        children = self.cache.graph.outputs[operation_id]
         if len(children) == 0:
             return
         self.cache.ensure_loaded()
@@ -332,13 +388,16 @@ class OperationSchema:
             if successor_id is None:
                 continue
             child_schema = self.cache.get_schema(child_operation)
-            if child_schema is not None and child_schema.change_cst_type(successor_id, ctype):
-                self._cascade_change_cst_type(successor_id, ctype, child_id)
+            if child_schema is None:
+                continue
+            if child_schema.change_cst_type(successor_id, ctype):
+                self._cascade_change_cst_type(child_id, successor_id, ctype)
 
     # pylint: disable=too-many-arguments
     def _cascade_update_cst(
         self,
-        cst_id: int, operation: int,
+        operation: int,
+        cst_id: int,
         data: dict, old_data: dict,
         mapping: CstMapping
     ) -> None:
@@ -366,30 +425,33 @@ class OperationSchema:
                 continue
             new_mapping = {alias_mapping[alias]: cst for alias, cst in new_mapping.items()}
             self._cascade_update_cst(
-                cst_id=successor_id,
                 operation=child_id,
+                cst_id=successor_id,
                 data=new_data,
                 old_data=new_old_data,
                 mapping=new_mapping
             )
 
-    def _cascade_before_delete(self, target: list[Constituenta], operation: int) -> None:
+    def _cascade_delete_inherited(self, operation: int, target: list[Constituenta]) -> None:
         children = self.cache.graph.outputs[operation]
         if len(children) == 0:
             return
         self.cache.ensure_loaded()
         for child_id in children:
-            child_operation = self.cache.operation_by_id[child_id]
-            child_schema = self.cache.get_schema(child_operation)
-            if child_schema is None:
-                continue
-            self._undo_substitutions_cst(target, child_operation, child_schema)
-            child_target_ids = self.cache.get_inheritors_list([cst.pk for cst in target], child_id)
-            child_target_cst = [child_schema.cache.by_id[cst_id] for cst_id in child_target_ids]
-            self._cascade_before_delete(child_target_cst, child_id)
-            if len(child_target_cst) > 0:
-                self.cache.remove_cst(child_target_ids, child_id)
-                child_schema.delete_cst(child_target_cst)
+            self._execute_delete_inherited(child_id, target)
+
+    def _execute_delete_inherited(self, operation_id: int, parent_cst: list[Constituenta]) -> None:
+        operation = self.cache.operation_by_id[operation_id]
+        schema = self.cache.get_schema(operation)
+        if schema is None:
+            return
+        self._undo_substitutions_cst(parent_cst, operation, schema)
+        target_ids = self.cache.get_inheritors_list([cst.pk for cst in parent_cst], operation_id)
+        target_cst = [schema.cache.by_id[cst_id] for cst_id in target_ids]
+        self._cascade_delete_inherited(operation_id, target_cst)
+        if len(target_cst) > 0:
+            self.cache.remove_cst(operation_id, target_ids)
+            schema.delete_cst(target_cst)
 
     def _cascade_before_substitute(self, substitutions: CstSubstitution, operation: Operation) -> None:
         children = self.cache.graph.outputs[operation.pk]
@@ -411,12 +473,12 @@ class OperationSchema:
         self,
         mapping: CstMapping,
         target: list[int],
-        operation: Operation,
+        operation: int,
         schema: RSForm
     ) -> None:
         alias_mapping = OperationSchema._produce_alias_mapping(mapping)
         schema.apply_partial_mapping(alias_mapping, target)
-        children = self.cache.graph.outputs[operation.pk]
+        children = self.cache.graph.outputs[operation]
         if len(children) == 0:
             return
         self.cache.ensure_loaded()
@@ -431,7 +493,7 @@ class OperationSchema:
             new_target = self.cache.get_inheritors_list(target, child_id)
             if len(new_target) == 0:
                 continue
-            self._cascade_partial_mapping(new_mapping, new_target, child_operation, child_schema)
+            self._cascade_partial_mapping(new_mapping, new_target, child_id, child_schema)
 
     @staticmethod
     def _produce_alias_mapping(mapping: CstMapping) -> dict[str, str]:
@@ -555,37 +617,66 @@ class OperationSchema:
             if sub.original_id in target_ids or sub.substitution_id in target_ids:
                 to_process.append(sub)
         for sub in to_process:
-            self._undo_substitution(sub, schema, target_ids)
+            self._undo_substitution(schema, sub, target_ids)
 
-    def _undo_substitution(self, target: Substitution, schema: RSForm, ignore_parents: list[int]) -> None:
-        operation = self.cache.operation_by_id[target.operation_id]
+    def _undo_substitution(
+        self,
+        schema: RSForm,
+        target: Substitution,
+        ignore_parents: Optional[list[int]] = None
+    ) -> None:
+        if ignore_parents is None:
+            ignore_parents = []
+        operation_id = target.operation_id
         original_schema, _, original_cst, substitution_cst = self.cache.unfold_sub(target)
 
         dependant = []
         for cst_id in original_schema.get_dependant([original_cst.pk]):
             if cst_id not in ignore_parents:
-                inheritor_id = self.cache.get_inheritor(cst_id, operation.pk)
+                inheritor_id = self.cache.get_inheritor(cst_id, operation_id)
                 if inheritor_id is not None:
                     dependant.append(inheritor_id)
 
-        self.cache.substitutions[operation.pk].remove(target)
+        self.cache.substitutions[operation_id].remove(target)
         target.delete()
 
         new_original: Optional[Constituenta] = None
         if original_cst.pk not in ignore_parents:
             full_cst = Constituenta.objects.get(pk=original_cst.pk)
-            self.after_create_cst([full_cst], original_schema)
-            new_original_id = self.cache.get_inheritor(original_cst.pk, operation.pk)
+            self.after_create_cst(original_schema, [full_cst])
+            new_original_id = self.cache.get_inheritor(original_cst.pk, operation_id)
             assert new_original_id is not None
             new_original = schema.cache.by_id[new_original_id]
         if len(dependant) == 0:
             return
 
-        substitution_id = self.cache.get_inheritor(substitution_cst.pk, operation.pk)
+        substitution_id = self.cache.get_inheritor(substitution_cst.pk, operation_id)
         assert substitution_id is not None
         substitution_inheritor = schema.cache.by_id[substitution_id]
         mapping = {cast(str, substitution_inheritor.alias): new_original}
-        self._cascade_partial_mapping(mapping, dependant, operation, schema)
+        self._cascade_partial_mapping(mapping, dependant, operation_id, schema)
+
+    def _process_added_substitutions(self, schema: Optional[RSForm], added: list[Substitution]) -> None:
+        if len(added) == 0:
+            return
+        if schema is None:
+            for sub in added:
+                self.cache.insert_substitution(sub)
+            return
+
+        cst_mapping: CstSubstitution = []
+        for sub in added:
+            original_id = self.cache.get_inheritor(sub.original_id, sub.operation_id)
+            substitution_id = self.cache.get_inheritor(sub.substitution_id, sub.operation_id)
+            if original_id is None or substitution_id is None:
+                raise ValueError('Substitutions not found.')
+            original_cst = schema.cache.by_id[original_id]
+            substitution_cst = schema.cache.by_id[substitution_id]
+            cst_mapping.append((original_cst, substitution_cst))
+        self.before_substitute(schema, cst_mapping)
+        schema.substitute(cst_mapping)
+        for sub in added:
+            self.cache.insert_substitution(sub)
 
 
 class OssCache:
@@ -608,11 +699,18 @@ class OssCache:
         self.substitutions: dict[int, list[Substitution]] = {}
         self.inheritance: dict[int, list[Inheritance]] = {}
 
-    def insert(self, schema: RSForm) -> None:
-        ''' Insert new schema. '''
-        if not self._schema_by_id.get(schema.model.pk):
-            schema.cache.ensure_loaded()
-            self._insert_new(schema)
+    def ensure_loaded(self) -> None:
+        ''' Ensure cache is fully loaded. '''
+        if self.is_loaded:
+            return
+        self.is_loaded = True
+        for operation in self.operations:
+            self.inheritance[operation.pk] = []
+            self.substitutions[operation.pk] = []
+        for sub in self._oss.substitutions().only('operation_id', 'original_id', 'substitution_id'):
+            self.substitutions[sub.operation_id].append(sub)
+        for item in self._oss.inheritance().only('operation_id', 'parent_id', 'child_id'):
+            self.inheritance[item.operation_id].append(item)
 
     def get_schema(self, operation: Operation) -> Optional[RSForm]:
         ''' Get schema by Operation. '''
@@ -633,19 +731,6 @@ class OssCache:
                 return operation
         raise ValueError(f'Operation for schema {schema} not found')
 
-    def ensure_loaded(self) -> None:
-        ''' Ensure cache is fully loaded. '''
-        if self.is_loaded:
-            return
-        self.is_loaded = True
-        for operation in self.operations:
-            self.inheritance[operation.pk] = []
-            self.substitutions[operation.pk] = []
-        for sub in self._oss.substitutions().only('operation_id', 'original_id', 'substitution_id'):
-            self.substitutions[sub.operation_id].append(sub)
-        for item in self._oss.inheritance().only('operation_id', 'parent_id', 'child_id'):
-            self.inheritance[item.operation_id].append(item)
-
     def get_inheritor(self, parent_cst: int, operation: int) -> Optional[int]:
         ''' Get child for parent inside target RSFrom. '''
         for item in self.inheritance[operation]:
@@ -668,6 +753,12 @@ class OssCache:
                 return self.get_inheritor(sub.substitution_id, operation)
         return self.get_inheritor(parent_cst, operation)
 
+    def insert_schema(self, schema: RSForm) -> None:
+        ''' Insert new schema. '''
+        if not self._schema_by_id.get(schema.model.pk):
+            schema.cache.ensure_loaded()
+            self._insert_new(schema)
+
     def insert_operation(self, operation: Operation) -> None:
         ''' Insert new operation. '''
         self.operations.append(operation)
@@ -677,6 +768,10 @@ class OssCache:
             self.substitutions[operation.pk] = []
             self.inheritance[operation.pk] = []
 
+    def insert_argument(self, argument: Argument) -> None:
+        ''' Insert new argument. '''
+        self.graph.add_edge(argument.operation_id, argument.argument_id)
+
     def insert_inheritance(self, inheritance: Inheritance) -> None:
         ''' Insert new inheritance. '''
         self.inheritance[inheritance.operation_id].append(inheritance)
@@ -685,7 +780,7 @@ class OssCache:
         ''' Insert new substitution. '''
         self.substitutions[sub.operation_id].append(sub)
 
-    def remove_cst(self, target: list[int], operation: int) -> None:
+    def remove_cst(self, operation: int, target: list[int]) -> None:
         ''' Remove constituents from operation. '''
         subs_to_delete = [
             sub for sub in self.substitutions[operation]
@@ -697,9 +792,15 @@ class OssCache:
         for item in inherit_to_delete:
             self.inheritance[operation].remove(item)
 
+    def remove_schema(self, schema: RSForm) -> None:
+        ''' Remove schema from cache. '''
+        self._schemas.remove(schema)
+        del self._schema_by_id[schema.model.pk]
+
     def remove_operation(self, operation: int) -> None:
         ''' Remove operation from cache. '''
         target = self.operation_by_id[operation]
+        self.graph.remove_node(operation)
         if target.result_id in self._schema_by_id:
             self._schemas.remove(self._schema_by_id[target.result_id])
             del self._schema_by_id[target.result_id]
@@ -709,10 +810,13 @@ class OssCache:
             del self.substitutions[operation]
             del self.inheritance[operation]
 
-    def remove_schema(self, schema: RSForm) -> None:
-        ''' Remove schema from cache. '''
-        self._schemas.remove(schema)
-        del self._schema_by_id[schema.model.pk]
+    def remove_argument(self, argument: Argument) -> None:
+        ''' Remove argument from cache. '''
+        self.graph.remove_edge(argument.operation_id, argument.argument_id)
+
+    def remove_substitution(self, target: Substitution) -> None:
+        ''' Remove substitution from cache. '''
+        self.substitutions[target.operation_id].remove(target)
 
     def unfold_sub(self, sub: Substitution) -> tuple[RSForm, RSForm, Constituenta, Constituenta]:
         operation = self.operation_by_id[sub.operation_id]
diff --git a/rsconcept/backend/apps/oss/models/PropagationFacade.py b/rsconcept/backend/apps/oss/models/PropagationFacade.py
index df3b9550..e0e5d230 100644
--- a/rsconcept/backend/apps/oss/models/PropagationFacade.py
+++ b/rsconcept/backend/apps/oss/models/PropagationFacade.py
@@ -14,39 +14,39 @@ class PropagationFacade:
     ''' Change propagation API. '''
 
     @staticmethod
-    def after_create_cst(new_cst: list[Constituenta], source: RSForm) -> None:
+    def after_create_cst(source: RSForm, new_cst: list[Constituenta]) -> None:
         ''' Trigger cascade resolutions when new constituent is created. '''
         hosts = _get_oss_hosts(source.model)
         for host in hosts:
-            OperationSchema(host).after_create_cst(new_cst, source)
+            OperationSchema(host).after_create_cst(source, new_cst)
 
     @staticmethod
-    def after_change_cst_type(target: Constituenta, source: RSForm) -> None:
+    def after_change_cst_type(source: RSForm, target: Constituenta) -> None:
         ''' Trigger cascade resolutions when constituenta type is changed. '''
         hosts = _get_oss_hosts(source.model)
         for host in hosts:
-            OperationSchema(host).after_change_cst_type(target, source)
+            OperationSchema(host).after_change_cst_type(source, target)
 
     @staticmethod
-    def after_update_cst(target: Constituenta, data: dict, old_data: dict, source: RSForm) -> None:
+    def after_update_cst(source: RSForm, target: Constituenta, data: dict, old_data: dict) -> None:
         ''' Trigger cascade resolutions when constituenta data is changed. '''
         hosts = _get_oss_hosts(source.model)
         for host in hosts:
-            OperationSchema(host).after_update_cst(target, data, old_data, source)
+            OperationSchema(host).after_update_cst(source, target, data, old_data)
 
     @staticmethod
-    def before_delete_cst(target: list[Constituenta], source: RSForm) -> None:
+    def before_delete_cst(source: RSForm, target: list[Constituenta]) -> None:
         ''' Trigger cascade resolutions before constituents are deleted. '''
         hosts = _get_oss_hosts(source.model)
         for host in hosts:
-            OperationSchema(host).before_delete_cst(target, source)
+            OperationSchema(host).before_delete_cst(source, target)
 
     @staticmethod
-    def before_substitute(substitutions: CstSubstitution, source: RSForm) -> None:
+    def before_substitute(source: RSForm, substitutions: CstSubstitution) -> None:
         ''' Trigger cascade resolutions before constituents are substituted. '''
         hosts = _get_oss_hosts(source.model)
         for host in hosts:
-            OperationSchema(host).before_substitute(substitutions, source)
+            OperationSchema(host).before_substitute(source, substitutions)
 
     @staticmethod
     def before_delete_schema(item: LibraryItem) -> None:
@@ -58,4 +58,4 @@ class PropagationFacade:
             return
 
         schema = RSForm(item)
-        PropagationFacade.before_delete_cst(list(schema.constituents()), schema)
+        PropagationFacade.before_delete_cst(schema, list(schema.constituents()))
diff --git a/rsconcept/backend/apps/oss/tests/s_propagation/t_constituents.py b/rsconcept/backend/apps/oss/tests/s_propagation/t_constituents.py
index 0d9ec899..a7b9f559 100644
--- a/rsconcept/backend/apps/oss/tests/s_propagation/t_constituents.py
+++ b/rsconcept/backend/apps/oss/tests/s_propagation/t_constituents.py
@@ -51,7 +51,7 @@ class TestChangeConstituents(EndpointTester):
             alias='3',
             operation_type=OperationType.SYNTHESIS
         )
-        self.owned.set_arguments(self.operation3, [self.operation1, self.operation2])
+        self.owned.set_arguments(self.operation3.pk, [self.operation1, self.operation2])
         self.owned.execute_operation(self.operation3)
         self.operation3.refresh_from_db()
         self.ks3 = RSForm(self.operation3.result)
diff --git a/rsconcept/backend/apps/oss/tests/s_propagation/t_operations.py b/rsconcept/backend/apps/oss/tests/s_propagation/t_operations.py
index 987030b3..eaff883e 100644
--- a/rsconcept/backend/apps/oss/tests/s_propagation/t_operations.py
+++ b/rsconcept/backend/apps/oss/tests/s_propagation/t_operations.py
@@ -71,8 +71,8 @@ class TestChangeOperations(EndpointTester):
             alias='4',
             operation_type=OperationType.SYNTHESIS
         )
-        self.owned.set_arguments(self.operation4, [self.operation1, self.operation2])
-        self.owned.set_substitutions(self.operation4, [{
+        self.owned.set_arguments(self.operation4.pk, [self.operation1, self.operation2])
+        self.owned.set_substitutions(self.operation4.pk, [{
             'original': self.ks1X1,
             'substitution': self.ks2S1
         }])
@@ -92,8 +92,8 @@ class TestChangeOperations(EndpointTester):
             alias='5',
             operation_type=OperationType.SYNTHESIS
         )
-        self.owned.set_arguments(self.operation5, [self.operation4, self.operation3])
-        self.owned.set_substitutions(self.operation5, [{
+        self.owned.set_arguments(self.operation5.pk, [self.operation4, self.operation3])
+        self.owned.set_substitutions(self.operation5.pk, [{
             'original': self.ks4X1,
             'substitution': self.ks3X1
         }])
@@ -249,3 +249,75 @@ class TestChangeOperations(EndpointTester):
         self.assertEqual(self.ks5.constituents().count(), 8)
         self.assertEqual(self.ks4D2.definition_formal, r'X1 X2 X3 S1 D1')
         self.assertEqual(self.ks5D4.definition_formal, r'X1 X2 X3 S1 D1 D2 D3')
+
+    @decl_endpoint('/api/oss/{item}/update-operation', method='patch')
+    def test_change_substitutions(self):
+        data = {
+            'target': self.operation4.pk,
+            'item_data': {
+                'alias': 'Test4 mod',
+                'title': 'Test title mod',
+                'comment': 'Comment mod'
+            },
+            'positions': [],
+            'substitutions': [
+                {
+                    'original': self.ks1X1.pk,
+                    'substitution': self.ks2X2.pk
+                },
+                {
+                    'original': self.ks2X1.pk,
+                    'substitution': self.ks1D1.pk
+                }
+            ]
+        }
+
+        self.executeOK(data=data, item=self.owned_id)
+        self.ks4D2.refresh_from_db()
+        self.ks5D4.refresh_from_db()
+        subs1_2 = self.operation4.getSubstitutions()
+        self.assertEqual(subs1_2.count(), 2)
+        subs3_4 = self.operation5.getSubstitutions()
+        self.assertEqual(subs3_4.count(), 1)
+        self.assertEqual(self.ks4.constituents().count(), 5)
+        self.assertEqual(self.ks5.constituents().count(), 7)
+        self.assertEqual(self.ks4D2.definition_formal, r'X1 D1 X3 S1 D1')
+        self.assertEqual(self.ks5D4.definition_formal, r'X1 D2 X3 S1 D1 D2 D3')
+
+    @decl_endpoint('/api/oss/{item}/update-operation', method='patch')
+    def test_change_arguments(self):
+        data = {
+            'target': self.operation4.pk,
+            'item_data': {
+                'alias': 'Test4 mod',
+                'title': 'Test title mod',
+                'comment': 'Comment mod'
+            },
+            'positions': [],
+            'arguments': [self.operation1.pk],
+        }
+
+        self.executeOK(data=data, item=self.owned_id)
+        self.ks4D2.refresh_from_db()
+        self.ks5D4.refresh_from_db()
+        subs1_2 = self.operation4.getSubstitutions()
+        self.assertEqual(subs1_2.count(), 0)
+        subs3_4 = self.operation5.getSubstitutions()
+        self.assertEqual(subs3_4.count(), 1)
+        self.assertEqual(self.ks4.constituents().count(), 4)
+        self.assertEqual(self.ks5.constituents().count(), 6)
+        self.assertEqual(self.ks4D2.definition_formal, r'X1 DEL DEL DEL D1')
+        self.assertEqual(self.ks5D4.definition_formal, r'X1 DEL DEL DEL D1 D2 D3')
+
+        data['arguments'] = [self.operation1.pk, self.operation2.pk]
+        self.executeOK(data=data, item=self.owned_id)
+        self.ks4D2.refresh_from_db()
+        self.ks5D4.refresh_from_db()
+        subs1_2 = self.operation4.getSubstitutions()
+        self.assertEqual(subs1_2.count(), 0)
+        subs3_4 = self.operation5.getSubstitutions()
+        self.assertEqual(subs3_4.count(), 1)
+        self.assertEqual(self.ks4.constituents().count(), 7)
+        self.assertEqual(self.ks5.constituents().count(), 9)
+        self.assertEqual(self.ks4D2.definition_formal, r'X1 DEL DEL DEL D1')
+        self.assertEqual(self.ks5D4.definition_formal, r'X1 DEL DEL DEL D1 D2 D3')
diff --git a/rsconcept/backend/apps/oss/tests/s_propagation/t_substitutions.py b/rsconcept/backend/apps/oss/tests/s_propagation/t_substitutions.py
index 7cc5ae26..1a383a42 100644
--- a/rsconcept/backend/apps/oss/tests/s_propagation/t_substitutions.py
+++ b/rsconcept/backend/apps/oss/tests/s_propagation/t_substitutions.py
@@ -71,8 +71,8 @@ class TestChangeSubstitutions(EndpointTester):
             alias='4',
             operation_type=OperationType.SYNTHESIS
         )
-        self.owned.set_arguments(self.operation4, [self.operation1, self.operation2])
-        self.owned.set_substitutions(self.operation4, [{
+        self.owned.set_arguments(self.operation4.pk, [self.operation1, self.operation2])
+        self.owned.set_substitutions(self.operation4.pk, [{
             'original': self.ks1X1,
             'substitution': self.ks2S1
         }])
@@ -92,8 +92,8 @@ class TestChangeSubstitutions(EndpointTester):
             alias='5',
             operation_type=OperationType.SYNTHESIS
         )
-        self.owned.set_arguments(self.operation5, [self.operation4, self.operation3])
-        self.owned.set_substitutions(self.operation5, [{
+        self.owned.set_arguments(self.operation5.pk, [self.operation4, self.operation3])
+        self.owned.set_substitutions(self.operation5.pk, [{
             'original': self.ks4X1,
             'substitution': self.ks3X1
         }])
diff --git a/rsconcept/backend/apps/oss/tests/s_views/t_oss.py b/rsconcept/backend/apps/oss/tests/s_views/t_oss.py
index 6937d9bb..ba52d035 100644
--- a/rsconcept/backend/apps/oss/tests/s_views/t_oss.py
+++ b/rsconcept/backend/apps/oss/tests/s_views/t_oss.py
@@ -55,8 +55,8 @@ class TestOssViewset(EndpointTester):
             alias='3',
             operation_type=OperationType.SYNTHESIS
         )
-        self.owned.set_arguments(self.operation3, [self.operation1, self.operation2])
-        self.owned.set_substitutions(self.operation3, [{
+        self.owned.set_arguments(self.operation3.pk, [self.operation1, self.operation2])
+        self.owned.set_substitutions(self.operation3.pk, [{
             'original': self.ks1X1,
             'substitution': self.ks2X1
         }])
diff --git a/rsconcept/backend/apps/oss/views/oss.py b/rsconcept/backend/apps/oss/views/oss.py
index 6a4a4dc5..adc70da8 100644
--- a/rsconcept/backend/apps/oss/views/oss.py
+++ b/rsconcept/backend/apps/oss/views/oss.py
@@ -129,7 +129,7 @@ class OssViewSet(viewsets.GenericViewSet, generics.ListAPIView, generics.Retriev
                 oss.create_input(new_operation)
             if new_operation.operation_type != m.OperationType.INPUT and 'arguments' in serializer.validated_data:
                 oss.set_arguments(
-                    operation=new_operation,
+                    target=new_operation.pk,
                     arguments=serializer.validated_data['arguments']
                 )
         return Response(
@@ -165,7 +165,7 @@ class OssViewSet(viewsets.GenericViewSet, generics.ListAPIView, generics.Retriev
         old_schema: Optional[LibraryItem] = operation.result
         with transaction.atomic():
             oss.update_positions(serializer.validated_data['positions'])
-            oss.delete_operation(operation, serializer.validated_data['keep_constituents'])
+            oss.delete_operation(operation.pk, serializer.validated_data['keep_constituents'])
             if old_schema is not None:
                 if serializer.validated_data['delete_schema']:
                     m.PropagationFacade.before_delete_schema(old_schema)
@@ -305,9 +305,9 @@ class OssViewSet(viewsets.GenericViewSet, generics.ListAPIView, generics.Retriev
                     operation.result.comment = operation.comment
                     operation.result.save()
             if 'arguments' in serializer.validated_data:
-                oss.set_arguments(operation, serializer.validated_data['arguments'])
+                oss.set_arguments(operation.pk, serializer.validated_data['arguments'])
             if 'substitutions' in serializer.validated_data:
-                oss.set_substitutions(operation, serializer.validated_data['substitutions'])
+                oss.set_substitutions(operation.pk, serializer.validated_data['substitutions'])
         return Response(
             status=c.HTTP_200_OK,
             data=s.OperationSchemaSerializer(oss.model).data
diff --git a/rsconcept/backend/apps/rsform/graph.py b/rsconcept/backend/apps/rsform/graph.py
index b6a749ad..bdb6ce6e 100644
--- a/rsconcept/backend/apps/rsform/graph.py
+++ b/rsconcept/backend/apps/rsform/graph.py
@@ -42,6 +42,28 @@ class Graph(Generic[ItemType]):
         if src not in self.inputs[dest]:
             self.inputs[dest].append(src)
 
+    def remove_edge(self, src: ItemType, dest: ItemType):
+        ''' Remove edge from graph. '''
+        if not self.contains(src) or not self.contains(dest):
+            return
+        if dest in self.outputs[src]:
+            self.outputs[src].remove(dest)
+        if src in self.inputs[dest]:
+            self.inputs[dest].remove(src)
+
+    def remove_node(self, target: ItemType):
+        ''' Remove node from graph. '''
+        if not self.contains(target):
+            return
+        del self.outputs[target]
+        del self.inputs[target]
+        for list_out in self.outputs.values():
+            if target in list_out:
+                list_out.remove(target)
+        for list_in in self.inputs.values():
+            if target in list_in:
+                list_in.remove(target)
+
     def expand_inputs(self, origin: Iterable[ItemType]) -> list[ItemType]:
         ''' Expand origin nodes forward through graph edges. '''
         result: list[ItemType] = []
diff --git a/rsconcept/backend/apps/rsform/tests/t_graph.py b/rsconcept/backend/apps/rsform/tests/t_graph.py
index 63713f95..3c99462a 100644
--- a/rsconcept/backend/apps/rsform/tests/t_graph.py
+++ b/rsconcept/backend/apps/rsform/tests/t_graph.py
@@ -26,6 +26,32 @@ class TestGraph(unittest.TestCase):
         self.assertTrue(graph.has_edge(1, 3))
         self.assertTrue(graph.has_edge(2, 1))
 
+    def test_remove_node(self):
+        graph = Graph({
+            1: [2],
+            2: [3, 5],
+            3: [],
+            5: []
+        })
+        self.assertEqual(len(graph.outputs), 4)
+        graph.remove_node(0)
+        graph.remove_node(2)
+        self.assertEqual(graph.outputs[1], [])
+        self.assertEqual(len(graph.outputs), 3)
+
+    def test_remove_edge(self):
+        graph = Graph({
+            1: [2],
+            2: [3, 5],
+            3: [],
+            5: []
+        })
+        graph.remove_edge(0, 1)
+        graph.remove_edge(2, 1)
+        self.assertEqual(graph.outputs[1], [2])
+        graph.remove_edge(1, 2)
+        self.assertEqual(graph.outputs[1], [])
+        graph.remove_edge(1, 2)
 
     def test_expand_outputs(self):
         graph = Graph({
diff --git a/rsconcept/backend/apps/rsform/views/rsforms.py b/rsconcept/backend/apps/rsform/views/rsforms.py
index 4499e836..1565da34 100644
--- a/rsconcept/backend/apps/rsform/views/rsforms.py
+++ b/rsconcept/backend/apps/rsform/views/rsforms.py
@@ -87,7 +87,7 @@ class RSFormViewSet(viewsets.GenericViewSet, generics.ListAPIView, generics.Retr
         schema = m.RSForm(self._get_item())
         with transaction.atomic():
             new_cst = schema.create_cst(data, insert_after)
-            PropagationFacade.after_create_cst([new_cst], schema)
+            PropagationFacade.after_create_cst(schema, [new_cst])
         return Response(
             status=c.HTTP_201_CREATED,
             data={
@@ -118,7 +118,7 @@ class RSFormViewSet(viewsets.GenericViewSet, generics.ListAPIView, generics.Retr
         data = serializer.validated_data['item_data']
         with transaction.atomic():
             old_data = schema.update_cst(cst, data)
-            PropagationFacade.after_update_cst(cst, data, old_data, schema)
+            PropagationFacade.after_update_cst(schema, cst, data, old_data)
         return Response(
             status=c.HTTP_200_OK,
             data=s.CstSerializer(m.Constituenta.objects.get(pk=request.data['target'])).data
@@ -159,7 +159,7 @@ class RSFormViewSet(viewsets.GenericViewSet, generics.ListAPIView, generics.Retr
 
         with transaction.atomic():
             new_cst = schema.produce_structure(cst, cst_parse)
-            PropagationFacade.after_create_cst(new_cst, schema)
+            PropagationFacade.after_create_cst(schema, new_cst)
         return Response(
             status=c.HTTP_200_OK,
             data={
@@ -197,7 +197,7 @@ class RSFormViewSet(viewsets.GenericViewSet, generics.ListAPIView, generics.Retr
             schema.save()
             cst.refresh_from_db()
             if changed_type:
-                PropagationFacade.after_change_cst_type(cst, schema)
+                PropagationFacade.after_change_cst_type(schema, cst)
         return Response(
             status=c.HTTP_200_OK,
             data={
@@ -233,7 +233,7 @@ class RSFormViewSet(viewsets.GenericViewSet, generics.ListAPIView, generics.Retr
                 original = cast(m.Constituenta, substitution['original'])
                 replacement = cast(m.Constituenta, substitution['substitution'])
                 substitutions.append((original, replacement))
-            PropagationFacade.before_substitute(substitutions, schema)
+            PropagationFacade.before_substitute(schema, substitutions)
             schema.substitute(substitutions)
         return Response(
             status=c.HTTP_200_OK,
@@ -263,7 +263,7 @@ class RSFormViewSet(viewsets.GenericViewSet, generics.ListAPIView, generics.Retr
         cst_list: list[m.Constituenta] = serializer.validated_data['items']
         schema = m.RSForm(model)
         with transaction.atomic():
-            PropagationFacade.before_delete_cst(cst_list, schema)
+            PropagationFacade.before_delete_cst(schema, cst_list)
             schema.delete_cst(cst_list)
         return Response(
             status=c.HTTP_200_OK,
@@ -581,7 +581,7 @@ def inline_synthesis(request: Request) -> HttpResponse:
 
     with transaction.atomic():
         new_items = receiver.insert_copy(items)
-        PropagationFacade.after_create_cst(new_items, receiver)
+        PropagationFacade.after_create_cst(receiver, new_items)
 
         substitutions: list[tuple[m.Constituenta, m.Constituenta]] = []
         for substitution in serializer.validated_data['substitutions']:
@@ -595,7 +595,7 @@ def inline_synthesis(request: Request) -> HttpResponse:
                 replacement = new_items[index]
             substitutions.append((original, replacement))
 
-        PropagationFacade.before_substitute(substitutions, receiver)
+        PropagationFacade.before_substitute(receiver, substitutions)
         receiver.substitute(substitutions)
 
         receiver.restore_order()
diff --git a/rsconcept/frontend/src/dialogs/DlgEditOperation/DlgEditOperation.tsx b/rsconcept/frontend/src/dialogs/DlgEditOperation/DlgEditOperation.tsx
index 81967b3a..876bd3cc 100644
--- a/rsconcept/frontend/src/dialogs/DlgEditOperation/DlgEditOperation.tsx
+++ b/rsconcept/frontend/src/dialogs/DlgEditOperation/DlgEditOperation.tsx
@@ -67,8 +67,8 @@ function DlgEditOperation({ hideWindow, oss, target, onSubmit }: DlgEditOperatio
     if (cache.loading || schemas.length !== schemasIDs.length) {
       return;
     }
-    setSubstitutions(prev =>
-      prev.filter(sub => {
+    setSubstitutions(() =>
+      target.substitutions.filter(sub => {
         const original = cache.getSchemaByCst(sub.original);
         if (!original || !schemasIDs.includes(original.id)) {
           return false;
@@ -80,7 +80,7 @@ function DlgEditOperation({ hideWindow, oss, target, onSubmit }: DlgEditOperatio
         return true;
       })
     );
-  }, [schemasIDs, schemas, cache.loading]);
+  }, [schemasIDs, schemas, cache.loading, target.substitutions]);
 
   const handleSubmit = () => {
     const data: IOperationUpdateData = {
diff --git a/rsconcept/frontend/src/pages/RSFormPage/MenuRSTabs.tsx b/rsconcept/frontend/src/pages/RSFormPage/MenuRSTabs.tsx
index 3fbce140..5a12c196 100644
--- a/rsconcept/frontend/src/pages/RSFormPage/MenuRSTabs.tsx
+++ b/rsconcept/frontend/src/pages/RSFormPage/MenuRSTabs.tsx
@@ -30,7 +30,7 @@ import Dropdown from '@/components/ui/Dropdown';
 import DropdownButton from '@/components/ui/DropdownButton';
 import { useAccessMode } from '@/context/AccessModeContext';
 import { useAuth } from '@/context/AuthContext';
-import { useLibrary } from '@/context/LibraryContext';
+import { useGlobalOss } from '@/context/GlobalOssContext';
 import { useConceptNavigation } from '@/context/NavigationContext';
 import { useRSForm } from '@/context/RSFormContext';
 import useDropdown from '@/hooks/useDropdown';
@@ -50,7 +50,7 @@ function MenuRSTabs({ onDestroy }: MenuRSTabsProps) {
   const router = useConceptNavigation();
   const { user } = useAuth();
   const model = useRSForm();
-  const library = useLibrary();
+  const oss = useGlobalOss();
 
   const { accessLevel, setAccessLevel } = useAccessMode();
 
@@ -185,11 +185,11 @@ function MenuRSTabs({ onDestroy }: MenuRSTabsProps) {
               onClick={handleCreateNew}
             />
           ) : null}
-          {library.globalOSS ? (
+          {oss.schema ? (
             <DropdownButton
               text='Перейти к ОСС'
               icon={<IconOSS size='1rem' className='icon-primary' />}
-              onClick={() => router.push(urls.oss(library.globalOSS!.id, OssTabID.GRAPH))}
+              onClick={() => router.push(urls.oss(oss.schema!.id, OssTabID.GRAPH))}
             />
           ) : null}
           <DropdownButton