diff --git a/comdel/display/component_display.cpp b/comdel/display/component_display.cpp
index 5a3b4fe..5cd65d9 100644
--- a/comdel/display/component_display.cpp
+++ b/comdel/display/component_display.cpp
@@ -97,11 +97,11 @@ void ComponentItem::contextMenuEvent(QGraphicsSceneContextMenuEvent *event) {
     });
     menu.addSeparator();
     for(auto attr: componentInstance->attributes) {
-        bool enabled = attr->attribute.getPopup().has_value();
+        bool enabled = attr.attribute.getPopup().has_value();
 
-        auto action = menu.addAction(QString::fromStdString("Izmjeni " + attr->name),
-                                     [attr, this]() {
-            DialogManager::updateAttribute(attr);
+        auto action = menu.addAction(QString::fromStdString("Izmjeni " + attr.name),
+                                     [&attr, this]() {
+            DialogManager::updateAttribute(&attr);
 
             this->redraw();
         });
diff --git a/comdel/display/schema_display.cpp b/comdel/display/schema_display.cpp
index 7bd27de..20c6515 100644
--- a/comdel/display/schema_display.cpp
+++ b/comdel/display/schema_display.cpp
@@ -15,13 +15,13 @@ void Schema::setSchema(domain::Schema* schema)
     this->schema = schema;
     if(schema != nullptr) {
         for(auto &instance: schema->componentInstances) {
-            ComponentWrapper *component = ComponentWrapper::ofComponent(&instance);
-            component->setPos(instance.position.first, instance.position.second);
+            ComponentWrapper *component = ComponentWrapper::ofComponent(instance.get());
+            component->setPos(instance->position.first, instance->position.second);
             scene.addItem(component);
         }
         for(auto &instance: schema->busInstances) {
-            ComponentWrapper *bus = ComponentWrapper::ofBus(&instance);
-            bus->setPos(instance.position.first, instance.position.second);
+            ComponentWrapper *bus = ComponentWrapper::ofBus(instance.get());
+            bus->setPos(instance->position.first, instance->position.second);
             scene.addItem(bus);
         }
     }
diff --git a/comdel/domain/comdelvalidator.cpp b/comdel/domain/comdelvalidator.cpp
index 9fd9295..f2fad6e 100644
--- a/comdel/domain/comdelvalidator.cpp
+++ b/comdel/domain/comdelvalidator.cpp
@@ -9,20 +9,20 @@ std::vector<ValidationError> ComdelValidator::validateSchema(Schema &schema, Val
     context.attribute = nullptr;
 
     for(auto &instance: schema.componentInstances) {
-        auto result = validateComponent(&instance, context);
+        auto result = validateComponent(instance.get(), context);
         errors.insert(errors.end(), result.begin(), result.end());
     }
     return errors;
 }
 
-std::vector<ValidationError> ComdelValidator::validateComponent(ComponentInstance *instance, ValidationContext context) {
+std::vector<ValidationError> ComdelValidator::validateComponent(ComponentInstance* instance, ValidationContext context) {
     std::vector<ValidationError> errors;
 
     context.instance = instance;
     context.attributes.clear();
 
     for(auto &attribute: instance->attributes) {
-        context.attributes[attribute->name] = attribute->value;
+        context.attributes[attribute.name] = attribute.value;
     }
 
     for(auto &rule: instance->component.getRules()) {
@@ -33,7 +33,7 @@ std::vector<ValidationError> ComdelValidator::validateComponent(ComponentInstanc
     }
 
     for(auto &attribute: instance->attributes) {
-        auto result = validateAttribute(attribute, context);
+        auto result = validateAttribute(&attribute, context);
         errors.insert(errors.end(), result.begin(), result.end());
     }
 
diff --git a/comdel/domain/connectioninstance.cpp b/comdel/domain/connectioninstance.cpp
index 2739065..963b787 100644
--- a/comdel/domain/connectioninstance.cpp
+++ b/comdel/domain/connectioninstance.cpp
@@ -3,15 +3,15 @@
 namespace domain {
 
 
-ConnectionInstance::ConnectionInstance(ComponentInstance *instance, std::vector<InstanceAttribute*> attributes, Connection connection)
+ConnectionInstance::ConnectionInstance(ComponentInstance *instance, std::vector<InstanceAttribute> attributes, Connection connection)
     : instance(instance), attributes(attributes), connection(connection)
 {}
 
-BusConnectionInstance::BusConnectionInstance(ComponentInstance *instance, std::vector<InstanceAttribute*> attributes, BusInstance *bus, Connection connection)
+BusConnectionInstance::BusConnectionInstance(ComponentInstance *instance, std::vector<InstanceAttribute> attributes, BusInstance *bus, Connection connection)
     : ConnectionInstance(instance, attributes, connection), bus(bus)
 {}
 
-DirectConnectionInstance::DirectConnectionInstance(ComponentInstance *instance, ComponentInstance *secondInstance, std::vector<InstanceAttribute*> attributes, BusInstance *bus, Connection connection)
+DirectConnectionInstance::DirectConnectionInstance(ComponentInstance *instance, ComponentInstance *secondInstance, std::vector<InstanceAttribute> attributes, BusInstance *bus, Connection connection)
     : ConnectionInstance(instance, attributes, connection), secondInstance(secondInstance), bus(bus)
 {}
 
diff --git a/comdel/domain/connectioninstance.h b/comdel/domain/connectioninstance.h
index 4c5101c..a04354c 100644
--- a/comdel/domain/connectioninstance.h
+++ b/comdel/domain/connectioninstance.h
@@ -17,9 +17,9 @@ public:
 
     virtual ~ConnectionInstance() = default;
 
-    std::vector<InstanceAttribute*> attributes;
+    std::vector<InstanceAttribute> attributes;
 
-    ConnectionInstance(ComponentInstance *instance, std::vector<InstanceAttribute*> attributes, Connection connection);
+    ConnectionInstance(ComponentInstance *instance, std::vector<InstanceAttribute> attributes, Connection connection);
 };
 
 
@@ -28,7 +28,7 @@ class BusConnectionInstance: public ConnectionInstance
 public:
     BusInstance *bus;
 
-    BusConnectionInstance(ComponentInstance *instance, std::vector<InstanceAttribute*> attributes, BusInstance *bus, Connection connection);
+    BusConnectionInstance(ComponentInstance *instance, std::vector<InstanceAttribute> attributes, BusInstance *bus, Connection connection);
 };
 
 
@@ -38,7 +38,7 @@ public:
     BusInstance *bus;
     ComponentInstance *secondInstance;
 
-    DirectConnectionInstance(ComponentInstance *instance, ComponentInstance *secondsInstance, std::vector<InstanceAttribute*> attributes, BusInstance *bus, Connection connection);
+    DirectConnectionInstance(ComponentInstance *instance, ComponentInstance *secondsInstance, std::vector<InstanceAttribute> attributes, BusInstance *bus, Connection connection);
 };
 
 
diff --git a/comdel/domain/instance.cpp b/comdel/domain/instance.cpp
index 016cb15..ebc97ff 100644
--- a/comdel/domain/instance.cpp
+++ b/comdel/domain/instance.cpp
@@ -3,13 +3,13 @@
 namespace domain {
 
 
-Instance::Instance(std::string name, std::vector<InstanceAttribute*> attributes, std::pair<int, int> position)
+Instance::Instance(std::string name, std::vector<InstanceAttribute> attributes, std::pair<int, int> position)
     : name(name), attributes(attributes), position(position)
 {}
 BusInstance::BusInstance(std::string name, std::pair<int, int> position, Bus bus, int size)
-    : Instance(name, vector<InstanceAttribute*>(), position), bus(bus), size(size)
+    : Instance(name, vector<InstanceAttribute>(), position), bus(bus), size(size)
 {}
-ComponentInstance::ComponentInstance(std::string name, std::vector<InstanceAttribute*> attributes, std::pair<int, int> position, Component component)
+ComponentInstance::ComponentInstance(std::string name, std::vector<InstanceAttribute> attributes, std::pair<int, int> position, Component component)
     : Instance(name, attributes, position), component(component)
 {}
 
diff --git a/comdel/domain/instance.h b/comdel/domain/instance.h
index b0dd129..8f45e29 100644
--- a/comdel/domain/instance.h
+++ b/comdel/domain/instance.h
@@ -16,12 +16,12 @@ class Instance
 {
 public:
     std::string name;
-    std::vector<InstanceAttribute*> attributes;
+    std::vector<InstanceAttribute> attributes;
     std::pair<int, int> position;
 
     virtual ~Instance() {};
 
-    Instance(std::string name, std::vector<InstanceAttribute*> attributes, std::pair<int, int> position);
+    Instance(std::string name, std::vector<InstanceAttribute> attributes, std::pair<int, int> position);
 };
 
 class BusInstance: public Instance
@@ -42,7 +42,7 @@ class ComponentInstance: public Instance
 public:
     Component component;
 
-    ComponentInstance(std::string name, std::vector<InstanceAttribute*> attributes, std::pair<int, int> position, Component component);
+    ComponentInstance(std::string name, std::vector<InstanceAttribute> attributes, std::pair<int, int> position, Component component);
 
     virtual ~ComponentInstance() {
         Instance::~Instance();
diff --git a/comdel/domain/schema.h b/comdel/domain/schema.h
index aa7732f..70ff7d5 100644
--- a/comdel/domain/schema.h
+++ b/comdel/domain/schema.h
@@ -15,20 +15,20 @@ public:
     Schema();
 
 
-    std::vector<BusInstance> busInstances;
-    std::vector<ComponentInstance> componentInstances;
+    std::vector<shared_ptr<BusInstance>> busInstances;
+    std::vector<shared_ptr<ComponentInstance>> componentInstances;
 
-    std::vector<ConnectionInstance> connections;
+    std::vector<shared_ptr<ConnectionInstance>> connections;
 
     Instance *getInstance(std::string& name) {
         for(auto& instance: busInstances) {
-            if (instance.name == name) {
-                return &instance;
+            if (instance->name == name) {
+                return instance.get();
             }
         }
         for(auto& instance: componentInstances) {
-            if (instance.name == name) {
-                return &instance;
+            if (instance->name == name) {
+                return instance.get();
             }
         }
         return nullptr;
diff --git a/comdel/domain/schemacreator.cpp b/comdel/domain/schemacreator.cpp
index 7a4ef66..0cffec4 100644
--- a/comdel/domain/schemacreator.cpp
+++ b/comdel/domain/schemacreator.cpp
@@ -803,7 +803,7 @@ Schema* SchemaCreator::loadSchema(SchemaNode node, Library &library)
             continue;
         }
 
-        std::vector<InstanceAttribute*> attributes;
+        std::vector<InstanceAttribute> attributes;
         for(auto& attr: conn.attributes) {
             if(connection->hasAttribute(attr.name.value)) {
                 auto attribute = connection->getAttribute(attr.name.value);
@@ -818,23 +818,23 @@ Schema* SchemaCreator::loadSchema(SchemaNode node, Library &library)
                     errors.emplace_back(attr.span, "invalid value");
                 }
 
-                attributes.push_back(new InstanceAttribute(attribute.getName(), toType(attr.value), attribute));
+                attributes.emplace_back(attribute.getName(), toType(attr.value), attribute);
             } else {
                 errors.emplace_back(attr.name.span, "unknown attribute");
             }
         }
 
         if(secondComponent == nullptr) {
-            schema->connections.push_back(BusConnectionInstance(firstComponent, attributes, bus, *connection));
+            schema->connections.push_back(std::make_shared<BusConnectionInstance>(firstComponent, attributes, bus, *connection));
         } else {
-            schema->connections.push_back(DirectConnectionInstance(firstComponent, secondComponent, attributes, bus, *connection));
+            schema->connections.push_back(std::make_shared<DirectConnectionInstance>(firstComponent, secondComponent, attributes, bus, *connection));
         }
     }
 
     return schema;
 }
 
-ComponentInstance SchemaCreator::loadComponentInstance(InstanceNode instance, Library &library) {
+shared_ptr<ComponentInstance> SchemaCreator::loadComponentInstance(InstanceNode instance, Library &library) {
 
     auto name = instance.name.value;
     auto position = std::make_pair(instance.position->first.value, instance.position->second.value);
@@ -842,19 +842,19 @@ ComponentInstance SchemaCreator::loadComponentInstance(InstanceNode instance, Li
     auto component = library.getComponent(instance.component.value);
 
     // validate attributes
-    std::vector<InstanceAttribute*> attributes;
+    std::vector<InstanceAttribute> attributes;
     for(auto& attr: instance.attributes) {
         if(component.hasAttribute(attr.name.value, toType(attr.value.getType()))) {
             auto attribute = component.getAttribute(attr.name.value);
-            attributes.emplace_back(new InstanceAttribute(attribute.getName(), toType(attr.value), attribute));
+            attributes.emplace_back(attribute.getName(), toType(attr.value), attribute);
         } else {
             errors.emplace_back(SourceError(attr.name.span, "unknown attribute"));
         }
     }
 
-    return {name, attributes, position, component};
+    return std::make_shared<ComponentInstance>(name, attributes, position, component);
 }
-BusInstance SchemaCreator::loadBusInstance(InstanceNode instance, Library &library) {
+std::shared_ptr<BusInstance> SchemaCreator::loadBusInstance(InstanceNode instance, Library &library) {
 
     auto name = instance.name.value;
     auto position = std::make_pair(instance.position->first.value, instance.position->second.value);
@@ -866,7 +866,7 @@ BusInstance SchemaCreator::loadBusInstance(InstanceNode instance, Library &libra
         size = instance.size->value;
     }
 
-    return {name, position, bus, static_cast<int>(size)};
+    return std::make_shared<BusInstance>(name, position, bus, static_cast<int>(size));
 }
 
 } // namespace domain
diff --git a/comdel/domain/schemacreator.h b/comdel/domain/schemacreator.h
index d29bf9d..d0360b1 100644
--- a/comdel/domain/schemacreator.h
+++ b/comdel/domain/schemacreator.h
@@ -75,8 +75,8 @@ class SchemaCreator
     std::optional<Connection> loadConnection(ConnectionNode node);
     std::optional<Bus> loadBus(BusNode node);
 
-    ComponentInstance loadComponentInstance(InstanceNode instance, Library &library);
-    BusInstance loadBusInstance(InstanceNode instance, Library &library);
+    std::shared_ptr<ComponentInstance> loadComponentInstance(InstanceNode instance, Library &library);
+    std::shared_ptr<BusInstance> loadBusInstance(InstanceNode instance, Library &library);
 
     std::optional<Bus> getBus(std::string name) {
         for(auto &bus: buses) {
@@ -113,7 +113,7 @@ class SchemaCreator
         this->context.push_back(context);
     }
     void pushAdditional(std::string name) {
-        if(this->context.size() > 0) {
+        if(!this->context.empty()) {
             this->context.push_back(current());
             current().name = name;
         } else {
diff --git a/mainwindow.cpp b/mainwindow.cpp
index 50d3776..ae94e16 100644
--- a/mainwindow.cpp
+++ b/mainwindow.cpp
@@ -157,25 +157,25 @@ void MainWindow::onStoreScheme() {
     buffer << "@schema {" << std::endl;
 
     for(auto &componentInstance: schema->componentInstances) {
-        buffer << "\t"   << "@instance " << componentInstance.name << " " << componentInstance.component.getName() << " {" << std::endl;
-        buffer << "\t\t" << "@position (" << componentInstance.position.first << ", " << componentInstance.position.second << ")" << std::endl;
+        buffer << "\t"   << "@instance " << componentInstance->name << " " << componentInstance->component.getName() << " {" << std::endl;
+        buffer << "\t\t" << "@position (" << componentInstance->position.first << ", " << componentInstance->position.second << ")" << std::endl;
 
-        for(auto &attribute: componentInstance.attributes) {
-            buffer << "\t\t" << "@attribute " << attribute->name << " " << attribute->value.stringify() << std::endl;
+        for(auto &attribute: componentInstance->attributes) {
+            buffer << "\t\t" << "@attribute " << attribute.name << " " << attribute.value.stringify() << std::endl;
         }
 
         buffer << "\t}" << std::endl << std::endl;
     }
 
     for(auto &busInstance: schema->busInstances) {
-        buffer << "\t"   << "@instance " << busInstance.name << " " << busInstance.bus.getName() << " {" << std::endl;
-        buffer << "\t\t" << "@position (" << busInstance.position.first << ", " << busInstance.position.second << ")" << std::endl;
-        buffer << "\t\t" << "@size " << busInstance.size << std::endl;
+        buffer << "\t"   << "@instance " << busInstance->name << " " << busInstance->bus.getName() << " {" << std::endl;
+        buffer << "\t\t" << "@position (" << busInstance->position.first << ", " << busInstance->position.second << ")" << std::endl;
+        buffer << "\t\t" << "@size " << busInstance->size << std::endl;
         buffer << "\t}" << std::endl << std::endl;
     }
 
     for(auto &conn: schema->connections) {
-        auto busConn = dynamic_cast<domain::BusConnectionInstance*>(&conn);
+        auto busConn = dynamic_cast<domain::BusConnectionInstance*>(conn.get());
         if(busConn) {
             buffer << "\t"  << "@connection (" << busConn->instance->name << "." << busConn->connection.getComponent().pin << ", " << busConn->bus->name << ") {" << std::endl;
             buffer << "\t"  << "}" << std::endl;