diff --git a/data_tools/tables_connection/tables_connection.cpp b/data_tools/tables_connection/tables_connection.cpp
index 0804e50..85e23e0 100644
--- a/data_tools/tables_connection/tables_connection.cpp
+++ b/data_tools/tables_connection/tables_connection.cpp
@@ -10,6 +10,8 @@ void TablesConnection::Setup(DataManager* manager, PlotArea* area) {
 // MARK: U.T. by Targets
 
 void TablesConnection::UpdateTable(const std::vector<gui::Target>& targets) {
+  DisableTablesConnections();
+
   if (targets.empty()) {
     targets_table_->setColumnCount(0);
     return;
@@ -27,7 +29,7 @@ void TablesConnection::UpdateTable(const std::vector<gui::Target>& targets) {
                                             item);  // номер к.т. = индекс + 1
 
     // в строки добавляем индекс на полотне и координаты
-    item = new QTableWidgetItem(QString::number(targets[i].GetIndexOnPlot()));
+    item = new QTableWidgetItem(QString::number(targets[i].GetData().GetId()));
     item->setFlags(Qt::ItemIsSelectable | Qt::ItemIsEnabled);
     targets_table_->setItem(0, static_cast<int>(i), item);
 
@@ -43,11 +45,14 @@ void TablesConnection::UpdateTable(const std::vector<gui::Target>& targets) {
   }
 
   targets_table_->update();
+  UpdateTablesConnections();
 }
 
 // MARK: U.T. by Hills
 
 void TablesConnection::UpdateTable(const std::vector<gui::Hill>& hills) {
+  DisableTablesConnections();
+
   if (hills.empty()) {
     hills_table_->setColumnCount(0);
     return;
@@ -75,7 +80,7 @@ void TablesConnection::UpdateTable(const std::vector<gui::Hill>& hills) {
                                           item);  // номер рельефа = индекс + 1
 
     // в строки добавляем индекс на полотне и координаты всех точек
-    item = new QTableWidgetItem(QString::number(hills[i].GetIndexOnPlot()));
+    item = new QTableWidgetItem(QString::number(hills[i].GetData().GetId()));
     item->setFlags(Qt::ItemIsSelectable | Qt::ItemIsEnabled);
     hills_table_->setItem(0, static_cast<int>(i), item);
 
@@ -104,12 +109,15 @@ void TablesConnection::UpdateTable(const std::vector<gui::Hill>& hills) {
   }
 
   hills_table_->update();
+  UpdateTablesConnections();
 }
 
 // MARK: U.T. by Tr. Lines
 
 void TablesConnection::UpdateTable(
     const std::vector<gui::TrappyLine>& trappy_lines) {
+  DisableTablesConnections();
+
   if (trappy_lines.empty()) {
     tr_lines_table_->setColumnCount(0);
     return;
@@ -127,8 +135,8 @@ void TablesConnection::UpdateTable(
                                              item);  // номер линии = индекс + 1
 
     // в строки добавляем индекс на полотне
-    item =
-        new QTableWidgetItem(QString::number(trappy_lines[i].GetIndexOnPlot()));
+    item = new QTableWidgetItem(
+        QString::number(trappy_lines[i].GetData().GetId()));
     item->setFlags(Qt::ItemIsSelectable | Qt::ItemIsEnabled);
     tr_lines_table_->setItem(0, static_cast<int>(i), item);
 
@@ -154,15 +162,27 @@ void TablesConnection::UpdateTable(
     item->setFlags(Qt::ItemIsSelectable | Qt::ItemIsEditable |
                    Qt::ItemIsEnabled);
     tr_lines_table_->setItem(2, static_cast<int>(i), item);
+
+    // если эти номера остались огромными, то валидные к.т. не нашлись
+    if (t_1_n == ULLONG_MAX || t_2_n == ULLONG_MAX) {
+      QMessageBox::warning(targets_table_.get(), "Error!",
+                           "Wrong targets numbers in TrappyLines!");
+
+      manager_->Remove(gui::ObjectType::TrappyLines, i);
+      area_->Redraw();
+    }
   }
 
   tr_lines_table_->update();
+  UpdateTablesConnections();
 }
 
 // MARK: U.T. by Tr. Circles
 
 void TablesConnection::UpdateTable(
     const std::vector<gui::TrappyCircle>& trappy_circles) {
+  DisableTablesConnections();
+
   if (trappy_circles.empty()) {
     tr_circles_table_->setColumnCount(0);
     return;
@@ -181,7 +201,7 @@ void TablesConnection::UpdateTable(
 
     // в строки добавляем индекс на полотне, координаты точки и радиус
     item = new QTableWidgetItem(
-        QString::number(trappy_circles[i].GetIndexOnPlot()));
+        QString::number(trappy_circles[i].GetData().GetId()));
     item->setFlags(Qt::ItemIsSelectable | Qt::ItemIsEnabled);
     tr_circles_table_->setItem(0, static_cast<int>(i), item);
 
@@ -204,6 +224,27 @@ void TablesConnection::UpdateTable(
   }
 
   tr_circles_table_->update();
+  UpdateTablesConnections();
+}
+
+void TablesConnection::UpdateTable(gui::ObjectType obj_type) {
+  switch (obj_type) {
+    case gui::ObjectType::Targets:
+      UpdateTable(manager_->GetTargets());
+      break;
+
+    case gui::ObjectType::Hills:
+      UpdateTable(manager_->GetHills());
+      break;
+
+    case gui::ObjectType::TrappyCircles:
+      UpdateTable(manager_->GetTrappyCircles());
+      break;
+
+    case gui::ObjectType::TrappyLines:
+      UpdateTable(manager_->GetTrappyLines());
+      break;
+  }
 }
 
 void TablesConnection::UpdateTables() {
@@ -234,7 +275,10 @@ void TablesConnection::TargetsItemChanged(int row, int column) {
 
   } catch (const std::exception& e) {
     manager_->Remove(gui::ObjectType::Targets, static_cast<size_t>(column));
-    UpdateTables();
+    UpdateTable(gui::ObjectType::Targets);
+
+    // (в случае удаления к.т., которая была привязана, надо обновить)
+    UpdateTable(gui::ObjectType::TrappyLines);
     area_->Redraw();
 
     QMessageBox::critical(targets_table_.get(), "Error!", e.what());
@@ -277,7 +321,7 @@ void TablesConnection::HillsItemChanged(int row, int column) {
 
   } catch (const std::exception& e) {
     manager_->Remove(gui::ObjectType::Hills, static_cast<size_t>(column));
-    UpdateTables();
+    UpdateTable(gui::ObjectType::Hills);
     area_->Redraw();
 
     QMessageBox::critical(targets_table_.get(), "Error!", e.what());
@@ -307,7 +351,7 @@ void TablesConnection::TrappyCirclesItemChanged(int row, int column) {
   } catch (const std::exception& e) {
     manager_->Remove(gui::ObjectType::TrappyCircles,
                      static_cast<size_t>(column));
-    UpdateTables();
+    UpdateTable(gui::ObjectType::TrappyCircles);
     area_->Redraw();
 
     QMessageBox::critical(targets_table_.get(), "Error!", e.what());
@@ -343,7 +387,7 @@ void TablesConnection::TrappyLinesItemChanged(int row, int column) {
 
   } catch (const std::exception& e) {
     manager_->Remove(gui::ObjectType::TrappyLines, static_cast<size_t>(column));
-    UpdateTables();
+    UpdateTable(gui::ObjectType::TrappyLines);
     area_->Redraw();
 
     QMessageBox::warning(targets_table_.get(), "Error!", e.what());
@@ -353,46 +397,74 @@ void TablesConnection::TrappyLinesItemChanged(int row, int column) {
 // MARK: Remove Items
 
 void TablesConnection::RemoveTargetItem() {
+  DisableTablesConnections();
+
   manager_->Remove(gui::ObjectType::Targets, selected_column_);
   area_->Redraw();
   UpdateTable(manager_->GetTargets());
   UpdateTable(manager_->GetTrappyLines());
+
+  UpdateTablesConnections();
 }
 
 void TablesConnection::RemoveHillItem() {
+  DisableTablesConnections();
+
   manager_->Remove(gui::ObjectType::Hills, selected_column_);
   area_->Redraw();
   UpdateTable(manager_->GetHills());
+
+  UpdateTablesConnections();
 }
 
 void TablesConnection::RemoveTrappyCircleItem() {
+  DisableTablesConnections();
+
   manager_->Remove(gui::ObjectType::TrappyCircles, selected_column_);
   area_->Redraw();
   UpdateTable(manager_->GetTrappyCircles());
+
+  UpdateTablesConnections();
 }
 
 void TablesConnection::RemoveTrappyLineItem() {
+  DisableTablesConnections();
+
   manager_->Remove(gui::ObjectType::TrappyLines, selected_column_);
   area_->Redraw();
   UpdateTable(manager_->GetTrappyLines());
+
+  UpdateTablesConnections();
 }
 
 // MARK: Update Connections
 
 void TablesConnection::UpdateTablesConnections() {
-  {
-    QObject::connect(targets_table_.get(), &QTableWidget::cellChanged, this,
-                     &TablesConnection::TargetsItemChanged);
+  QObject::connect(targets_table_.get(), &QTableWidget::cellChanged, this,
+                   &TablesConnection::TargetsItemChanged);
 
-    QObject::connect(hills_table_.get(), &QTableWidget::cellChanged, this,
-                     &TablesConnection::HillsItemChanged);
+  QObject::connect(hills_table_.get(), &QTableWidget::cellChanged, this,
+                   &TablesConnection::HillsItemChanged);
 
-    QObject::connect(tr_circles_table_.get(), &QTableWidget::cellChanged, this,
-                     &TablesConnection::TrappyCirclesItemChanged);
+  QObject::connect(tr_circles_table_.get(), &QTableWidget::cellChanged, this,
+                   &TablesConnection::TrappyCirclesItemChanged);
 
-    QObject::connect(tr_lines_table_.get(), &QTableWidget::cellChanged, this,
-                     &TablesConnection::TrappyLinesItemChanged);
-  }
+  QObject::connect(tr_lines_table_.get(), &QTableWidget::cellChanged, this,
+                   &TablesConnection::TrappyLinesItemChanged);
+}
+
+void TablesConnection::DisableTablesConnections() {
+  QObject::disconnect(targets_table_.get(), &QTableWidget::cellChanged, this,
+                      &TablesConnection::TargetsItemChanged);
+
+  QObject::disconnect(hills_table_.get(), &QTableWidget::cellChanged, this,
+                      &TablesConnection::HillsItemChanged);
+
+  QObject::disconnect(tr_circles_table_.get(), &QTableWidget::cellChanged, this,
+                      &TablesConnection::TrappyCirclesItemChanged);
+
+  QObject::disconnect(tr_lines_table_.get(), &QTableWidget::cellChanged, this,
+                      &TablesConnection::TrappyLinesItemChanged);
 }
 
 void TablesConnection::UpdateRemoveButtonConnections() {
diff --git a/data_tools/tables_connection/tables_connection.h b/data_tools/tables_connection/tables_connection.h
index d23914a..d1fece4 100644
--- a/data_tools/tables_connection/tables_connection.h
+++ b/data_tools/tables_connection/tables_connection.h
@@ -52,28 +52,10 @@ class TablesConnection : public QObject {
   void UpdateTables();
 
   /**
-   * @brief Обновляет значения таблицы с Targets
-   * @param targets: вектор новых значений
-   */
-  void UpdateTable(const std::vector<gui::Target>& targets);
-
-  /**
-   * @brief Обновляет значения таблицы с Hills
-   * @param hills: вектор новых значений
+   * @brief Обновляет значения таблицы с определенным типом объекта
+   * @param obj_type: тип объекта
    */
-  void UpdateTable(const std::vector<gui::Hill>& hills);
-
-  /**
-   * @brief Обновляет значения таблицы с TrappyLines
-   * @param trappy_lines: вектор новых значений
-   */
-  void UpdateTable(const std::vector<gui::TrappyLine>& trappy_lines);
-
-  /**
-   * @brief Обновляет значения таблицы с TrappyCircles
-   * @param trappy_circles: вектор новых значений
-   */
-  void UpdateTable(const std::vector<gui::TrappyCircle>& trappy_circles);
+  void UpdateTable(gui::ObjectType obj_type);
 
  private slots:
   void TargetsItemChanged(int row, int column);
@@ -125,8 +107,33 @@ class TablesConnection : public QObject {
   }
 
  private:
+  /**
+   * @brief Обновляет значения таблицы с Targets
+   * @param targets: вектор новых значений
+   */
+  void UpdateTable(const std::vector<gui::Target>& targets);
+
+  /**
+   * @brief Обновляет значения таблицы с Hills
+   * @param hills: вектор новых значений
+   */
+  void UpdateTable(const std::vector<gui::Hill>& hills);
+
+  /**
+   * @brief Обновляет значения таблицы с TrappyLines
+   * @param trappy_lines: вектор новых значений
+   */
+  void UpdateTable(const std::vector<gui::TrappyLine>& trappy_lines);
+
+  /**
+   * @brief Обновляет значения таблицы с TrappyCircles
+   * @param trappy_circles: вектор новых значений
+   */
+  void UpdateTable(const std::vector<gui::TrappyCircle>& trappy_circles);
+
   int selected_column_{INT_MAX};
   void UpdateTablesConnections();
+  void DisableTablesConnections();
   void UpdateRemoveButtonConnections();
 
   std::unique_ptr<QTableWidget> targets_table_{nullptr};
diff --git a/gui/airport.cpp b/gui/airport.cpp
index ec360f5..7e1718d 100644
--- a/gui/airport.cpp
+++ b/gui/airport.cpp
@@ -2,7 +2,7 @@
 
 void gui::Airport::Draw(QCustomPlot* plot) {
   Target::Draw(plot);
-  auto graph = plot->graph(static_cast<int>(Target::GetIndexOnPlot()));
+  auto graph = Target::GetGraphPtr();
 
   graph->setPen(QColor(0, 0, 0, 255));
   graph->setScatterStyle(QCPScatterStyle(QCPScatterStyle::ssCrossCircle, 10));
diff --git a/gui/base.h b/gui/base.h
index b00ee9f..36adb27 100644
--- a/gui/base.h
+++ b/gui/base.h
@@ -15,17 +15,6 @@ class Drawable {
    */
   virtual void Draw(QCustomPlot* plot) = 0;
 
-  /**
-   * @brief Возвращает индекс на полотне [plottable]
-   * @return size_t: индекс
-   */
-  virtual size_t GetIndexOnPlot() const { return index_on_plot_; }
-
- protected:
-  virtual void SetIndexOnPlot(QCustomPlot* plot) {
-    index_on_plot_ = plot->plottableCount() - 1;
-  }
-
  private:
   size_t index_on_plot_{ULLONG_MAX};
 };
diff --git a/gui/hill.cpp b/gui/hill.cpp
index 0646104..f110230 100644
--- a/gui/hill.cpp
+++ b/gui/hill.cpp
@@ -24,7 +24,4 @@ void gui::Hill::Draw(QCustomPlot* plot) {
 
   // замыкаем, соединяя с первой точкой
   curve_->addData(points[0].x, points[0].y);
-
-  // индекс последнего созданного = кол-во всех - 1
-  SetIndexOnPlot(plot);
 }
diff --git a/gui/target.cpp b/gui/target.cpp
index d207660..174a7c1 100644
--- a/gui/target.cpp
+++ b/gui/target.cpp
@@ -10,7 +10,4 @@ void gui::Target::Draw(QCustomPlot* plot) {
   graph_->setScatterStyle(QCPScatterStyle(QCPScatterStyle::ssCircle, 4));
 
   graph_->setData({GetPoint().x}, {GetPoint().y});
-
-  // индекс последнего созданного = кол-во всех - 1
-  SetIndexOnPlot(plot);
 }
diff --git a/gui/trappy_circle.cpp b/gui/trappy_circle.cpp
index 719e76a..5ebdd7d 100644
--- a/gui/trappy_circle.cpp
+++ b/gui/trappy_circle.cpp
@@ -14,7 +14,4 @@ void gui::TrappyCircle::Draw(QCustomPlot* plot) {
                                GetCenter().y + GetRadius());
   ellipse_->bottomRight->setCoords(GetCenter().x + GetRadius(),
                                    GetCenter().y - GetRadius());
-
-  // индекс последнего созданного = кол-во всех - 1
-  SetIndexOnPlot(plot);
 }
diff --git a/gui/trappy_circle.h b/gui/trappy_circle.h
index 6cc54a1..7c39578 100644
--- a/gui/trappy_circle.h
+++ b/gui/trappy_circle.h
@@ -39,15 +39,6 @@ class TrappyCircle : public Drawable {
 
   void Draw(QCustomPlot* plot) override;
 
-  /**
-   * @brief Возвращает индекс на полотне [item]
-   * @details Этот метод перегружен у TrappyCircle, так как его фигуры на
-   * полотне являются QCPItemEllipse, которые в свою очередь относятся к Items,
-   * а не Plottables по отношению к QCustomPlot plot
-   * @return size_t: индекс
-   */
-  size_t GetIndexOnPlot() const override { return item_index_; }
-
   /**
    * @brief Возвращает значение указателя на полотне
    * @return QCPItemEllipse*: указатель
@@ -59,10 +50,6 @@ class TrappyCircle : public Drawable {
   }
 
  private:
-  void SetIndexOnPlot(QCustomPlot* plot) override {
-    item_index_ = plot->itemCount() - 1;
-  }
-
   lib::TrappyCircle data_;
   QColor color_;
   size_t item_index_{ULLONG_MAX};
diff --git a/gui/trappy_line.cpp b/gui/trappy_line.cpp
index 18b4190..001940a 100644
--- a/gui/trappy_line.cpp
+++ b/gui/trappy_line.cpp
@@ -20,9 +20,6 @@ void TrappyLine::Draw(QCustomPlot* plot) {
 
   graph_->addData(targets.first.GetPoint().x, targets.first.GetPoint().y);
   graph_->addData(targets.second.GetPoint().x, targets.second.GetPoint().y);
-
-  // индекс последнего созданного = кол-во всех - 1
-  SetIndexOnPlot(plot);
 }
 
 void TrappyLine::UpdateData(gui::Target* first_target,
diff --git a/lib/hill.cpp b/lib/hill.cpp
index e661dfa..0d9bd4f 100644
--- a/lib/hill.cpp
+++ b/lib/hill.cpp
@@ -47,7 +47,10 @@ void Hill::SetJsonInfo(const QJsonObject& hill_obj) {
     vertices_.push_back(vertice);
   }
 
-  SetId(static_cast<unsigned short>(hill_obj.value("Id").toInt()));
+  unsigned short id = static_cast<unsigned short>(hill_obj.value("Id").toInt());
+  if (id < 40000 || id > 49999)
+    throw std::invalid_argument("Invalid file format: incorrect id in 'Hill'!");
+  SetId(id);
 
   CheckErrorValues();
 }
diff --git a/lib/target.cpp b/lib/target.cpp
index 19b2f32..dd4601f 100644
--- a/lib/target.cpp
+++ b/lib/target.cpp
@@ -16,14 +16,18 @@ void Target::SetJsonInfo(const QJsonObject& target_obj) {
   if (!(target_obj.contains("X") && target_obj.contains("Y") &&
         target_obj.contains("Id")))
     throw std::invalid_argument(
-        "Invalid file format: missing X,Y or Id field in Targets!");
+        "Invalid file format: missing X, Y or Id field in Targets!");
 
   double x = target_obj.value("X").toDouble();
   double y = target_obj.value("Y").toDouble();
-
   SetPoint(x, y);
 
-  SetId(static_cast<unsigned short>(target_obj.value("Id").toInt()));
+  unsigned short id =
+      static_cast<unsigned short>(target_obj.value("Id").toInt());
+  if (id < 10000 || id > 19999)
+    throw std::invalid_argument(
+        "Invalid file format: incorrect id in 'Target'!");
+  SetId(id);
 
   CheckErrorValues();
 }
diff --git a/lib/trappy_circle.cpp b/lib/trappy_circle.cpp
index 87e2979..b51d888 100644
--- a/lib/trappy_circle.cpp
+++ b/lib/trappy_circle.cpp
@@ -39,7 +39,12 @@ void TrappyCircle::SetJsonInfo(const QJsonObject& trappy_circle_obj) {
   SetCenter({x, y});
   SetRadius(r);
 
-  SetId(static_cast<unsigned short>(trappy_circle_obj.value("Id").toInt()));
+  unsigned short id =
+      static_cast<unsigned short>(trappy_circle_obj.value("Id").toInt());
+  if (id < 20000 || id > 29999)
+    throw std::invalid_argument(
+        "Invalid file format: incorrect id in 'Trappy_Circle'!");
+  SetId(id);
 
   CheckErrorValues();
 }
diff --git a/main/gui_json_file/gui_json_file.h b/main/gui_json_file/gui_json_file.h
index 2f57194..fb8de03 100644
--- a/main/gui_json_file/gui_json_file.h
+++ b/main/gui_json_file/gui_json_file.h
@@ -11,20 +11,20 @@ class GuiJsonFile {
 
   void Save(data_tools::DataManager* plot_area);
   void Open(data_tools::DataManager* plot_area);
+  void Close() { file_->close(); }
 
   QString GetFileName() const {
     return QString::fromStdString(
         file_->filesystemFileName().filename().string());
   }
 
-  QString GetParentPath() const {
-    return QString::fromStdString(
-        file_->filesystemFileName().parent_path().string());
+  QString GetAbsolutePath() const {
+    return QString::fromStdString(file_->filesystemFileName().string());
   }
 
-  QString GetRelativePath() const {
+  QString GetParentPath() const {
     return QString::fromStdString(
-        file_->filesystemFileName().relative_path().string());
+        file_->filesystemFileName().parent_path().string());
   }
 
   void SetFile(const QString& file_name) { file_->setFileName(file_name); }
diff --git a/main/gui_json_file/open.cpp b/main/gui_json_file/open.cpp
index b867bd2..2a59b4e 100644
--- a/main/gui_json_file/open.cpp
+++ b/main/gui_json_file/open.cpp
@@ -30,6 +30,13 @@ std::vector<lib::Hill> GetHillsFromFile(QJsonArray arr) {
   return hills;
 }
 
+bool IsExistId(std::vector<unsigned short> ids, unsigned short curr_id) {
+  for (const auto& id : ids) {
+    if (curr_id == id) return true;
+  }
+  return false;
+}
+
 void GuiJsonFile::Open(data_tools::DataManager* manager) {
   if (file_->open(QIODevice::ReadOnly | QFile::Text)) {
     QJsonObject root = LoadJson();
@@ -46,38 +53,83 @@ void GuiJsonFile::Open(data_tools::DataManager* manager) {
 
     std::vector<lib::Target> targets;
 
+    std::vector<unsigned short> targets_ids;
     for (size_t i = 0; i < static_cast<size_t>(json_targets.size()); i++) {
       lib::Target t;
       t.SetJsonInfo(json_targets.at(i).toObject());
       targets.push_back(t);
+
+      if (IsExistId(targets_ids, t.GetId()))
+        throw std::invalid_argument(
+            "Invalid file format: there are identical id's in 'Targets'!");
+
+      targets_ids.push_back(t.GetId());
     }
     manager->Set(GetTargetsFromFile(json_targets));
 
+    std::vector<unsigned short> trappy_circles_ids;
     for (size_t i = 0; i < static_cast<size_t>(json_trappy_circles.size());
          i++) {
       lib::TrappyCircle trc;
       trc.SetJsonInfo(json_trappy_circles.at(i).toObject());
+
+      if (IsExistId(trappy_circles_ids, trc.GetId()))
+        throw std::invalid_argument(
+            "Invalid file format: there are identical id's in "
+            "'Trappy_Circles'!");
+
+      trappy_circles_ids.push_back(trc.GetId());
     }
     manager->Set(GetTrappyCirclesFromFile(json_trappy_circles));
 
+    std::vector<unsigned short> trappy_lines_ids;
     for (size_t i = 0; i < static_cast<size_t>(json_trappy_lines.size()); i++) {
       QJsonObject json_tr_line = json_trappy_lines.at(i).toObject();
+
       unsigned short id1 =
           static_cast<unsigned short>(json_tr_line.value("Id_P1").toInt());
       unsigned short id2 =
           static_cast<unsigned short>(json_tr_line.value("Id_P2").toInt());
+
       std::pair<gui::Target*, gui::Target*> targets_ptrs;
       for (const auto& target : manager->GetTargetsPtrs()) {
         if (target->GetData().GetId() == id1) targets_ptrs.first = target;
         if (target->GetData().GetId() == id2) targets_ptrs.second = target;
       }
-      manager->Add(
-          new gui::TrappyLine(targets_ptrs.first, targets_ptrs.second));
+
+      if (targets_ptrs.first == nullptr || targets_ptrs.second == nullptr)
+        throw std::invalid_argument(
+            "Invalid file format: non-existent id for 'Target' in "
+            "'Trappy_Line'!");
+
+      gui::TrappyLine* trl{
+          new gui::TrappyLine(targets_ptrs.first, targets_ptrs.second)};
+
+      unsigned short id =
+          static_cast<unsigned short>(json_tr_line.value("Id").toInt());
+      if (IsExistId(trappy_lines_ids, id))
+        throw std::invalid_argument(
+            "Invalid file format: there are identical id's in "
+            "'Trappy_Lines'!");
+      if (id < 30000 || id > 39999)
+        throw std::invalid_argument(
+            "Invalid file format: incorrect id in 'Trappy_Line'!");
+
+      trappy_lines_ids.push_back(id);
+      trl->GetData().SetId(id);
+      manager->Add(trl);
     }
 
+    std::vector<unsigned short> hills_ids;
     for (size_t i = 0; i < static_cast<size_t>(json_hills.size()); i++) {
       lib::Hill h;
       h.SetJsonInfo(json_hills.at(i).toObject());
+
+      if (IsExistId(hills_ids, h.GetId()))
+        throw std::invalid_argument(
+            "Invalid file format: there are identical id's in 'Hills'!");
+
+      hills_ids.push_back(h.GetId());
     }
     manager->Set(GetHillsFromFile(json_hills));
 
diff --git a/main/mainwindow.cpp b/main/mainwindow.cpp
index 6a7f1b5..25b6cd4 100644
--- a/main/mainwindow.cpp
+++ b/main/mainwindow.cpp
@@ -12,9 +12,6 @@ MainWindow::MainWindow(QWidget* parent)
   ui->plot->setInteractions(QCP::iRangeDrag | QCP::iRangeZoom |
                             QCP::iSelectPlottables | QCP::iSelectItems);
 
-  connect(ui->plot, &QCustomPlot::mouseDoubleClick, this,
-          &MainWindow::mousePressObjectsButton);
-
   connect(ui->plot, &QCustomPlot::mousePress, this,
           &MainWindow::mousePressContextMenu);
 
diff --git a/main/mainwindow_connections/interaction_buttons.cpp b/main/mainwindow_connections/interaction_buttons.cpp
index 6f131e2..8a9e845 100644
--- a/main/mainwindow_connections/interaction_buttons.cpp
+++ b/main/mainwindow_connections/interaction_buttons.cpp
@@ -32,8 +32,8 @@ void MainWindow::DisconnectObject(gui::ObjectType obj_type) {
       break;
   }
 
-  connect(ui->plot, &QCustomPlot::mouseDoubleClick, this,
-          &MainWindow::mousePressObjectsButton);
+  disconnect(ui->plot, &QCustomPlot::mouseDoubleClick, this,
+             &MainWindow::mousePressObjectsButton);
   connect(ui->plot, &QCustomPlot::mousePress, this,
           &MainWindow::mousePressContextMenu);
 
@@ -70,7 +70,6 @@ void MainWindow::DeleteLastAddedObject() {
   }
 
   area_->Redraw();
-  t_connection_->UpdateTables();
 
   what_obj_addition_ = WhatObjectAddition::Nothing;
 }
@@ -96,6 +95,9 @@ void MainWindow::mousePressObjectsButton(QMouseEvent* mouse_event) {
 
         ui->plot->setCursor(Qt::CrossCursor);
         cursor_ = CursorType::DefaultCursor;
+
+        // после финального добавления обновляем таблицу
+        t_connection_->UpdateTable(gui::ObjectType::Targets);
         break;
       }
 
@@ -161,7 +163,6 @@ void MainWindow::mousePressObjectsButton(QMouseEvent* mouse_event) {
     }
 
     area_->Redraw();
-    t_connection_->UpdateTables();
 
   } catch (const std::exception& e) {
     QMessageBox::critical(this, "Error!", e.what());
@@ -172,8 +173,11 @@ void MainWindow::mousePressSetRadiusFromPlot(QMouseEvent* mouse_event) {
   if (mouse_event->button() == Qt::LeftButton) {
     DisconnectObject(gui::ObjectType::TrappyCircles);
     what_obj_addition_ = WhatObjectAddition::Nothing;
+
     area_->Redraw();
-    t_connection_->UpdateTables();
+
+    // после финального добавления обновляем таблицу
+    t_connection_->UpdateTable(gui::ObjectType::TrappyCircles);
   }
 }
 
@@ -214,7 +218,9 @@ void MainWindow::mousePressSelectSecondTarget(QMouseEvent* mouse_event) {
       what_obj_addition_ = WhatObjectAddition::Nothing;
 
       area_->Redraw();
-      t_connection_->UpdateTables();
+
+      // после финального добавления обновляем таблицу
+      t_connection_->UpdateTable(gui::ObjectType::TrappyLines);
 
       return;
     }
@@ -251,6 +257,9 @@ void MainWindow::mousePressAddVertice(QMouseEvent* mouse_event) {
       DisconnectObject(gui::ObjectType::Hills);
       what_obj_addition_ = WhatObjectAddition::Nothing;
 
+      // после финального добавления обновляем таблицу
+      t_connection_->UpdateTable(gui::ObjectType::Hills);
+
     } else if (manager_->GetHills()[last].GetPoints()[0] ==
                manager_->GetHills()[last].GetPoints()[1]) {
       size_t last_p = manager_->GetHills()[last].GetPoints().size() - 1;
@@ -261,7 +270,6 @@ void MainWindow::mousePressAddVertice(QMouseEvent* mouse_event) {
       manager_->GetHillsPtrs()[last]->AddVertice({x, y});
 
     area_->Redraw();
-    t_connection_->UpdateTables();
   }
 }
 
@@ -283,7 +291,6 @@ void MainWindow::mousePressDeleteLastVertice(QMouseEvent* mouse_event) {
     }
 
     area_->Redraw();
-    t_connection_->UpdateTables();
   }
 }
 
diff --git a/main/mainwindow_connections/menu_add_actions.cpp b/main/mainwindow_connections/menu_add_actions.cpp
index afbd94b..1d83689 100644
--- a/main/mainwindow_connections/menu_add_actions.cpp
+++ b/main/mainwindow_connections/menu_add_actions.cpp
@@ -42,7 +42,7 @@ void MainWindow::AddTarget(std::string x, std::string y) {
 
     manager_->Add(new gui::Target(std::stod(x), std::stod(y)));
     area_->Redraw();
-    t_connection_->UpdateTables();
+    t_connection_->UpdateTable(gui::ObjectType::Targets);
 
   } catch (const std::exception& e) {
     QMessageBox::critical(this, "Error!", e.what());
@@ -57,7 +57,7 @@ void MainWindow::AddTrappyCircle(std::string x, std::string y,
     manager_->Add(
         new gui::TrappyCircle(std::stod(x), std::stod(y), std::stod(radius)));
     area_->Redraw();
-    t_connection_->UpdateTables();
+    t_connection_->UpdateTable(gui::ObjectType::TrappyCircles);
 
   } catch (const std::exception& e) {
     QMessageBox::critical(this, "Error!", e.what());
@@ -77,7 +77,7 @@ void MainWindow::AddTrappyLine(std::string x1, std::string y1, std::string x2,
         manager_->GetTargetsPtrs()[manager_->GetTargets().size() - 1]));
 
     area_->Redraw();
-    t_connection_->UpdateTables();
+    t_connection_->UpdateTable(gui::ObjectType::TrappyLines);
 
   } catch (const std::exception& e) {
     QMessageBox::critical(this, "Error!", e.what());
@@ -96,7 +96,7 @@ void MainWindow::AddHill(
     manager_->Add(new gui::Hill(lib_points));
 
     area_->Redraw();
-    t_connection_->UpdateTables();
+    t_connection_->UpdateTable(gui::ObjectType::Hills);
 
   } catch (const std::exception& e) {
     QMessageBox::critical(this, "Error!", e.what());
diff --git a/main/mainwindow_connections/menu_file_actions.cpp b/main/mainwindow_connections/menu_file_actions.cpp
index a68b1ab..65faf8b 100644
--- a/main/mainwindow_connections/menu_file_actions.cpp
+++ b/main/mainwindow_connections/menu_file_actions.cpp
@@ -96,20 +96,23 @@ void MainWindow::on_actionOpen_triggered() {
 
   if (file_name.isEmpty()) return;
 
-  QString old_filename = json_file_.GetFileName();
+  QString old_filename = json_file_.GetAbsolutePath();
 
   try {
     json_file_.SetFile(file_name);
     manager_->Clear();
     json_file_.Open(manager_.get());
-    area_->Redraw();
-    t_connection_->UpdateTables();
 
   } catch (const std::exception& e) {
     QMessageBox::critical(this, "Error!", e.what());
-
+    json_file_.Close();
+    manager_->Clear();
     json_file_.SetFile(old_filename);
+    json_file_.Open(manager_.get());
   }
+
+  area_->Redraw();
+  t_connection_->UpdateTables();
 }
 
 // Кнопка "Save"
@@ -131,7 +134,7 @@ bool MainWindow::on_actionSave_as_triggered() {
   DeleteLastAddedObject();
 
   QString file_name = QFileDialog::getSaveFileName(
-      this, tr("Save as"), json_file_.GetRelativePath(), tr("File (*.json)"));
+      this, tr("Save as"), json_file_.GetParentPath(), tr("File (*.json)"));
 
   if (!file_name.isEmpty()) {
     json_file_.SetFile(file_name);
@@ -139,4 +142,4 @@ bool MainWindow::on_actionSave_as_triggered() {
     return false;
   }
   return true;
-}
\ No newline at end of file
+}
diff --git a/main/mainwindow_connections/other_connections.cpp b/main/mainwindow_connections/other_connections.cpp
index 841c87c..e39a80d 100644
--- a/main/mainwindow_connections/other_connections.cpp
+++ b/main/mainwindow_connections/other_connections.cpp
@@ -15,6 +15,8 @@ gui::ObjectType MainWindow::GetObjType() const {
 
 void MainWindow::on_pushButtonAddTarget_clicked() {
   DeleteLastAddedObject();
+  connect(ui->plot, &QCustomPlot::mouseDoubleClick, this,
+          &MainWindow::mousePressObjectsButton);
 
   ui->plot->setCursor(QCursor(QPixmap("../images/better_cross_cursor.png")
                                   .scaled(QSize(24, 24), Qt::KeepAspectRatio)));
@@ -23,6 +25,8 @@ void MainWindow::on_pushButtonAddTarget_clicked() {
 
 void MainWindow::on_pushButtonAddTrappyCircle_clicked() {
   DeleteLastAddedObject();
+  connect(ui->plot, &QCustomPlot::mouseDoubleClick, this,
+          &MainWindow::mousePressObjectsButton);
 
   ui->plot->setCursor(QCursor(QPixmap("../images/move_cursor.png")
                                   .scaled(QSize(24, 24), Qt::KeepAspectRatio)));
@@ -31,6 +35,8 @@ void MainWindow::on_pushButtonAddTrappyCircle_clicked() {
 
 void MainWindow::on_pushButtonAddTrappyLine_clicked() {
   DeleteLastAddedObject();
+  connect(ui->plot, &QCustomPlot::mouseDoubleClick, this,
+          &MainWindow::mousePressObjectsButton);
 
   ui->plot->setCursor(QCursor(QPixmap("../images/choose_cursor.png")
                                   .scaled(QSize(24, 24), Qt::KeepAspectRatio)));
@@ -39,6 +45,8 @@ void MainWindow::on_pushButtonAddTrappyLine_clicked() {
 
 void MainWindow::on_pushButtonAddHill_clicked() {
   DeleteLastAddedObject();
+  connect(ui->plot, &QCustomPlot::mouseDoubleClick, this,
+          &MainWindow::mousePressObjectsButton);
 
   ui->plot->setCursor(QCursor(QPixmap("../images/move_cursor.png")
                                   .scaled(QSize(24, 24), Qt::KeepAspectRatio)));
@@ -98,44 +106,50 @@ void MainWindow::mousePressRemoveObject() {
       if (ui->plot->selectedGraphs()[0] ==
           manager_->GetTargetsPtrs()[i]->GetGraphPtr()) {
         manager_->Remove(gui::ObjectType::Targets, i);
+        t_connection_->UpdateTable(gui::ObjectType::Targets);
         is_found = true;
         break;
       }
     }
+
     if (!is_found)
       for (size_t i = 0; i < manager_->GetTrappyLines().size(); i++) {
         if (ui->plot->selectedGraphs()[0] ==
             manager_->GetTrappyLinesPtrs()[i]->GetGraphPtr()) {
           manager_->Remove(gui::ObjectType::TrappyLines, i);
+          t_connection_->UpdateTable(gui::ObjectType::TrappyLines);
           break;
         }
       }
+
   } else if (ui->plot->selectedPlottables().size() > 0) {
     for (size_t i = 0; i < manager_->GetHills().size(); i++) {
       if (ui->plot->selectedPlottables()[0] ==
           manager_->GetHillsPtrs()[i]->GetCurvePtr()) {
         manager_->Remove(gui::ObjectType::Hills, i);
+        t_connection_->UpdateTable(gui::ObjectType::Hills);
         break;
       }
     }
+
   } else if (ui->plot->selectedItems().size() > 0)
     for (size_t i = 0; i < manager_->GetTrappyCircles().size(); i++) {
       if (ui->plot->selectedItems()[0] ==
           manager_->GetTrappyCirclesPtrs()[i]->GetItemEllipsePtr()) {
         manager_->Remove(gui::ObjectType::TrappyCircles, i);
+        t_connection_->UpdateTable(gui::ObjectType::TrappyCircles);
         break;
       }
     }
 
   area_->Redraw();
-  t_connection_->UpdateTables();
 }
 
 void MainWindow::mousePressContextMenu(QMouseEvent* mouse_event) {
   if (mouse_event->button() == Qt::RightButton &&
-      (ui->plot->selectedGraphs().size() > 0 ||
-       ui->plot->selectedItems().size() > 0 ||
-       ui->plot->selectedPlottables().size() > 0)) {
+      (!ui->plot->selectedGraphs().empty() ||
+       !ui->plot->selectedItems().empty() ||
+       !ui->plot->selectedPlottables().empty())) {
     ui->plot->setContextMenuPolicy(Qt::ActionsContextMenu);
 
     QMenu* menu{new QMenu(this)};