diff --git a/comdel/display/component_display.cpp b/comdel/display/component_display.cpp
index 14cd4ae..d9a89e0 100644
--- a/comdel/display/component_display.cpp
+++ b/comdel/display/component_display.cpp
@@ -5,7 +5,6 @@
 
 #include <QMenu>
 #include <QGraphicsSceneContextMenuEvent>
-#include <QGraphicsScene>
 #include <iostream>
 
 namespace display {
@@ -46,4 +45,24 @@ void Bus::contextMenuEvent(QGraphicsSceneContextMenuEvent *event) {
     menu.exec(event->screenPos());
 }
 
+    QVariant BusGroup::itemChange(QGraphicsItem::GraphicsItemChange change, const QVariant &value) {
+        if (change == ItemPositionChange && scene()) {
+            // value is the new position.
+            QPointF newPos = value.toPointF();
+            busInstance->position.first = newPos.x();
+            busInstance->position.second = newPos.y();
+        }
+        return QGraphicsItem::itemChange(change, value);
+    }
+
+
+    QVariant ComponentGroup::itemChange(QGraphicsItem::GraphicsItemChange change, const QVariant &value) {
+        if (change == ItemPositionChange && scene()) {
+            // value is the new position.
+            QPointF newPos = value.toPointF();
+            componentInstance->position.first = newPos.x();
+            componentInstance->position.second = newPos.y();
+        }
+        return QGraphicsItem::itemChange(change, value);
+    }
 } // namespace display
diff --git a/comdel/display/component_display.h b/comdel/display/component_display.h
index c782767..1fbe5e1 100644
--- a/comdel/display/component_display.h
+++ b/comdel/display/component_display.h
@@ -24,9 +24,12 @@ private:
     std::shared_ptr<domain::ComponentInstance> instance;
 public:
     Component(const std::shared_ptr<domain::ComponentInstance>& instance): instance(instance) {
+        setFlag(ItemSendsGeometryChanges, true);
+
         instance->component.getDisplay().render(this);
     }
     void contextMenuEvent(QGraphicsSceneContextMenuEvent *event) override;
+
 };
 
 class Bus: public QGraphicsItemGroup
@@ -37,6 +40,7 @@ public:
         instance->bus.getDisplay()->render(this);
     }
     void contextMenuEvent(QGraphicsSceneContextMenuEvent *event) override;
+
 };
 
 class ComponentGroup: public QGraphicsItemGroup
@@ -47,6 +51,8 @@ private:
 public:
     explicit ComponentGroup(const std::shared_ptr<domain::ComponentInstance>& instance): componentInstance(instance) {
         setFlag(ItemIsMovable, true);
+        setFlag(ItemSendsGeometryChanges, true);
+
         setHandlesChildEvents(false);
 
         addToGroup(new display::Component(instance));
@@ -57,6 +63,10 @@ public:
 
         setPos(instance->position.first, instance->position.second);
     }
+
+protected:
+    virtual QVariant itemChange(GraphicsItemChange change, const QVariant &value);
+
 };
 
 class BusGroup: public QGraphicsItemGroup
@@ -67,14 +77,21 @@ private:
 public:
     explicit BusGroup(const std::shared_ptr<domain::BusInstance>& instance): busInstance(instance) {
         setFlag(ItemIsMovable, true);
+        setFlag(ItemSendsGeometryChanges, true);
+
         setHandlesChildEvents(false);
 
         addToGroup(new display::Bus(instance));
 
         setPos(instance->position.first, instance->position.second);
     }
+
+protected:
+    virtual QVariant itemChange(GraphicsItemChange change, const QVariant &value);
 };
 
+
+
 } // namespace display
 
 #endif // DISPLAY_COMPONENT_H
diff --git a/comdel/domain/schemacreator.cpp b/comdel/domain/schemacreator.cpp
index a52b7a1..aa14599 100644
--- a/comdel/domain/schemacreator.cpp
+++ b/comdel/domain/schemacreator.cpp
@@ -946,7 +946,7 @@ vector<Enumeration> SchemaCreator::createWireEnumeration(vector<Value> wireValue
 }
 
 std::optional<Attribute> SchemaCreator::createMemoryAttribute() {
-    return Attribute("_memory", Value::fromMemoryReference(nullopt), createMemoryPopup());
+    return Attribute("_memory", Value::fromMemoryReference(std::nullopt), createMemoryPopup());
 }
 
     std::optional<Popup> SchemaCreator::createMemoryPopup() {
diff --git a/comdel/domain/value.cpp b/comdel/domain/value.cpp
index 54ba553..805342f 100644
--- a/comdel/domain/value.cpp
+++ b/comdel/domain/value.cpp
@@ -162,10 +162,10 @@ std::string Value::stringify() {
         case ATTRIBUTE_REFERENCE:
             return reference;
         case MEMORY_REFERENCE:
-            if(memoryReference->empty()) {
-                return "null";
-            } else {
+            if(memoryReference.has_value()) {
                 return memoryReference.value();
+            } else {
+                return "null";
             }
         default:
             throw std::exception();
diff --git a/comdel/domain/value.h b/comdel/domain/value.h
index 3af0497..c011ef4 100644
--- a/comdel/domain/value.h
+++ b/comdel/domain/value.h
@@ -29,22 +29,20 @@ public:
     };
 
 private:
-    long long intValue;
+    long long intValue = 0;
     std::string stringValue;
-    bool boolValue;
-    std::optional<AddressSpace> addressSpace;
+    bool boolValue = false;
+    std::optional<AddressSpace> addressSpace = std::nullopt;
     std::string reference;
-    domain::ComponentInstance *memory;
+    domain::ComponentInstance *memory = nullptr;
 
-    std::optional<std::string> memoryReference;
+    std::optional<std::string> memoryReference = std::nullopt;
 
-    ValueType type;
+    ValueType type = UNDEFINED;
 
 public:
 
-    Value() {
-        this->type = UNDEFINED;
-    }
+    Value() {}
 
     bool equals(Value value) {
         if(value.getType() == type) {