diff --git a/pglab/ConnectionConfigurationWidget.cpp b/pglab/ConnectionConfigurationWidget.cpp
index 979b909..6bf5d18 100644
--- a/pglab/ConnectionConfigurationWidget.cpp
+++ b/pglab/ConnectionConfigurationWidget.cpp
@@ -14,38 +14,43 @@
 #include <QSpinBox>
 #include <QComboBox>
 #include <QDialog>
+#include <QDebug>
 
 #define SET_OBJECT_NAME(var) var->setObjectName(#var)
 
 void ConnectionConfigurationWidget::editExistingInWindow(ConnectionController *ctrl, const ConnectionConfig &cfg)
 {
-	auto w = new ConnectionConfigurationWidget(ctrl->getConnectionTreeModel());
-	w->setData(cfg);
+	try {
+		auto w = new ConnectionConfigurationWidget(ctrl->getConnectionTreeModel());
+		w->setData(cfg);
 
+		auto btn_hbox = new QDialogButtonBox(QDialogButtonBox::Ok | QDialogButtonBox::Cancel, Qt::Horizontal);
+		//auto btn_test = btn_hbox->addButton(tr("Test"), QDialogButtonBox::ActionRole);
 
-	auto btn_hbox = new QDialogButtonBox(QDialogButtonBox::Ok | QDialogButtonBox::Cancel, Qt::Horizontal);
-	//auto btn_test = btn_hbox->addButton(tr("Test"), QDialogButtonBox::ActionRole);
+		auto vbox = new QVBoxLayout;
+		vbox->addWidget(w);
+		vbox->addWidget(btn_hbox);
 
-	auto vbox = new QVBoxLayout;
-	vbox->addWidget(w);
-	vbox->addWidget(btn_hbox);
+		auto win = new QDialog;
+		win->setWindowTitle(tr("Edit connection configuration"));
+		win->setLayout(vbox);
+		win->setAttribute( Qt::WA_DeleteOnClose, true );
 
-	auto win = new QDialog;
-	win->setWindowTitle(tr("Edit connection configuration"));
-	win->setLayout(vbox);
-	win->setAttribute( Qt::WA_DeleteOnClose, true );
-
-	win->connect(btn_hbox, &QDialogButtonBox::accepted, [ctrl, w, win] () {
-		auto [grp, cc] = w->data();
-		ctrl->getConnectionTreeModel()->save(grp, cc);
-		win->accept();
-	});
-	win->connect(btn_hbox, &QDialogButtonBox::rejected, [win] ()
-		{
-			win->reject();
+		QObject::connect(btn_hbox, &QDialogButtonBox::accepted, [ctrl, w, win] () {
+			auto [grp, cc] = w->data();
+			ctrl->getConnectionTreeModel()->save(grp, cc);
+			win->accept();
 		});
+		QObject::connect(btn_hbox, &QDialogButtonBox::rejected, [win] ()
+			{
+				win->reject();
+			});
 
-	win->show();
+		win->show();
+	}
+	catch (const std::exception &ex) {
+		qDebug() << "exception: " << QString::fromUtf8(ex.what());
+	}
 }
 
 ConnectionConfigurationWidget::ConnectionConfigurationWidget(ConnectionTreeModel *connection_model, QWidget *parent)
diff --git a/pglab/ConnectionListModel.cpp b/pglab/ConnectionListModel.cpp
index ede4713..8864165 100644
--- a/pglab/ConnectionListModel.cpp
+++ b/pglab/ConnectionListModel.cpp
@@ -366,7 +366,7 @@ std::tuple<int, int> ConnectionTreeModel::findConfig(const QUuid uuid) const
 	return { group_idx, connection_idx };
 }
 
-int ConnectionTreeModel::findGroup(QString name) const
+int ConnectionTreeModel::findGroup(const QString &name) const
 {
 	for (int idx = 0; idx < m_groups.size(); ++idx) {
 		if (m_groups[idx]->name == name) return idx;
@@ -374,7 +374,7 @@ int ConnectionTreeModel::findGroup(QString name) const
 	return -1;
 }
 
-std::variant<int, QSqlError> ConnectionTreeModel::addGroup(QString group_name)
+std::variant<int, QSqlError> ConnectionTreeModel::addGroup(const QString &group_name)
 {
 	QSqlQuery q(m_db);
 	q.prepare("INSERT INTO conngroup (gname) VALUES (:name)");
diff --git a/pglab/ConnectionListModel.h b/pglab/ConnectionListModel.h
index 515add6..8a21db8 100644
--- a/pglab/ConnectionListModel.h
+++ b/pglab/ConnectionListModel.h
@@ -61,7 +61,7 @@ public:
 	 */
 	void save(const ConnectionConfig &cc);
 	/// Create a new group in the DB and place in the tree
-	std::variant<int, QSqlError> addGroup(QString group_name);
+	std::variant<int, QSqlError> addGroup(const QString &group_name);
 	std::optional<QSqlError> removeGroup(int row);
 	int findGroup(int conngroup_id) const;
 
@@ -77,7 +77,7 @@ private:
 	/// Finds the connection with the specified uuid and returns
 	/// { group_index, connection_index }
 	std::tuple<int, int> findConfig(const QUuid uuid) const;
-	int findGroup(QString name) const;
+	int findGroup(const QString &name) const;
 
 	std::optional<QSqlError> saveToDb(const ConnectionConfig &cc);
 };
diff --git a/pglab/ConnectionManagerWindow.h b/pglab/ConnectionManagerWindow.h
index c72b9cb..29fedf0 100644
--- a/pglab/ConnectionManagerWindow.h
+++ b/pglab/ConnectionManagerWindow.h
@@ -20,7 +20,7 @@ class ConnectionManagerWindow : public QMainWindow {
 	Q_OBJECT
 public:
 	explicit ConnectionManagerWindow(MasterController *master, QWidget *parent = nullptr);
-	~ConnectionManagerWindow();
+	~ConnectionManagerWindow() override;
 
 private slots:
 	void on_actionAdd_Connection_triggered();
diff --git a/pglablib/ConnectionConfig.h b/pglablib/ConnectionConfig.h
index d08b6ca..452e723 100644
--- a/pglablib/ConnectionConfig.h
+++ b/pglablib/ConnectionConfig.h
@@ -139,7 +139,7 @@ private:
 	std::string m_encodedPassword;
 
 	bool m_dirty = false;
-	ConnectionGroup* m_group;
+	ConnectionGroup* m_group = nullptr;
 
 
 	static void strToEnv(QProcessEnvironment &env, const QString &var, const std::string &val);