diff --git a/libqf/libqfcore/src/core/utils.cpp b/libqf/libqfcore/src/core/utils.cpp
index bd93b6c4c..63e9014f6 100644
--- a/libqf/libqfcore/src/core/utils.cpp
+++ b/libqf/libqfcore/src/core/utils.cpp
@@ -5,6 +5,7 @@
 #include <QSet>
 #include <QDate>
 #include <QRegularExpression>
+#include <QJsonDocument>
 
 namespace qf::core {
 
@@ -266,4 +267,22 @@ QStringList Utils::parseProgramAndArgumentsList(const QString &command_line)
 	return args;
 }
 
+QVariant Utils::jsonToQVariant(const QString &json)
+{
+	QJsonParseError error;
+	auto doc = QJsonDocument::fromJson(json.toUtf8(), &error);
+	if (error.error != QJsonParseError::NoError) {
+		qfError() << json << "Json parse error:" << error.errorString();
+		return {};
+	}
+	return doc.toVariant();
+}
+
+QString Utils::qvariantToJson(const QVariant &v, bool compact)
+{
+	auto doc = QJsonDocument::fromVariant(v);
+	auto ba = doc.toJson(compact? QJsonDocument::Compact: QJsonDocument::Indented);
+	return QString::fromUtf8(ba);
+}
+
 }
diff --git a/libqf/libqfcore/src/core/utils.h b/libqf/libqfcore/src/core/utils.h
index 8c460f129..7290b23bb 100644
--- a/libqf/libqfcore/src/core/utils.h
+++ b/libqf/libqfcore/src/core/utils.h
@@ -210,6 +210,9 @@ class QFCORE_DECL_EXPORT Utils
 	}
 
 	static QStringList parseProgramAndArgumentsList(const QString &command_line);
+
+	static QVariant jsonToQVariant(const QString &json);
+	static QString qvariantToJson(const QVariant &v, bool compact = true);
 };
 
 }}
diff --git a/quickevent/app/quickevent/plugins/Classes/src/drawing/ganttitem.cpp b/quickevent/app/quickevent/plugins/Classes/src/drawing/ganttitem.cpp
index 68f3d1f59..5afc179f2 100644
--- a/quickevent/app/quickevent/plugins/Classes/src/drawing/ganttitem.cpp
+++ b/quickevent/app/quickevent/plugins/Classes/src/drawing/ganttitem.cpp
@@ -28,7 +28,7 @@ GanttItem::GanttItem(QGraphicsItem *parent)
 
 int GanttItem::startSlotItemIndex(const StartSlotItem *it) const
 {
-	return m_startSlotItems.indexOf((StartSlotItem *)it);
+	return m_startSlotItems.indexOf(it);
 }
 
 StartSlotItem *GanttItem::startSlotItemAt(int ix, bool throw_ex)
@@ -65,7 +65,7 @@ void GanttItem::load(int stage_id)
 	qfLogFuncFrame();
 	Event::StageData stage_data = getPlugin<EventPlugin>()->stageData(stage_id);
 	DrawingConfig dc(stage_data.drawingConfig());
-	QVariantList stsllst = dc.startSlots();
+	QVariantList start_slot_list = dc.startSlots();
 
 	qfs::Query q(qfs::Connection::forName());
 	qf::core::sql::QueryBuilder qb1;
@@ -104,7 +104,7 @@ void GanttItem::load(int stage_id)
 			if(slot_ix > curr_slot_ix) {
 				slot_item = addStartSlotItem();
 				curr_slot_ix = slot_ix;
-				StartSlotData sd(stsllst.value(slot_ix).toMap());
+				StartSlotData sd(start_slot_list.value(slot_ix).toMap());
 				slot_item->setData(sd);
 			}
 		}
@@ -114,8 +114,13 @@ void GanttItem::load(int stage_id)
 				slot_item = addStartSlotItem();
 			}
 		}
-		auto *class_it = slot_item->addClassItem();
-		class_it->setData(cd);
+		if (slot_item) {
+			auto *class_it = slot_item->addClassItem();
+			class_it->setData(cd);
+		}
+		else {
+			QF_EXCEPTION("internal error");
+		}
 	}
 	updateGeometry();
 	checkClassClash();
@@ -134,8 +139,7 @@ void GanttItem::save(int stage_id)
 			start_slots << sd;
 		}
 		dc.setStartSlots(start_slots);
-		QJsonDocument jsd = QJsonDocument::fromVariant(dc);
-		QString dc_str = QString::fromUtf8(jsd.toJson(QJsonDocument::Compact));
+		auto dc_str = qf::core::Utils::qvariantToJson(dc);
 
 		QString qs = "UPDATE stages SET drawingConfig=:drawingConfig WHERE id=:id";
 		qfs::Query q(qfs::Connection::forName());
diff --git a/quickevent/app/quickevent/plugins/Event/src/eventplugin.cpp b/quickevent/app/quickevent/plugins/Event/src/eventplugin.cpp
index 1e19eedf1..d482d0243 100644
--- a/quickevent/app/quickevent/plugins/Event/src/eventplugin.cpp
+++ b/quickevent/app/quickevent/plugins/Event/src/eventplugin.cpp
@@ -245,7 +245,14 @@ StageData EventPlugin::stageData(int stage_id)
 		doc.load(stage_id);
 		StageData data;
 		for (const auto &[k, v] : doc.values().asKeyValueRange()) {
-			data[k.toLower()] = v;
+			auto key = k.toLower();
+			if (key == "drawingconfig" && v.userType() == qMetaTypeId<QString>()) {
+				// convert json to variantmap
+				data[key] = qf::core::Utils::jsonToQVariant(v.toString());
+			}
+			else {
+				data[key] = v;
+			}
 		}
 		m_stageCache[stage_id] = StageData(data);
 	}
diff --git a/quickevent/app/quickevent/plugins/Event/src/stage.h b/quickevent/app/quickevent/plugins/Event/src/stage.h
index 7aac6aea0..f52c79399 100644
--- a/quickevent/app/quickevent/plugins/Event/src/stage.h
+++ b/quickevent/app/quickevent/plugins/Event/src/stage.h
@@ -14,9 +14,7 @@ class StageData : public QVariantMap
 private:
 	typedef QVariantMap Super;
 
-	// QF_VARIANTMAP_KEY_FIELD(int, id, i, setI, d)
 	QF_VARIANTMAP_KEY_FIELD(bool, useallmaps, is, set, UseAllMaps)
-	//QF_VARIANTMAP_KEY_FIELD(QDateTime, startdatetime, s, setS, tartDateTime)
 	QF_VARIANTMAP_KEY_FIELD(QVariantMap, drawingconfig, d, setD, rawingConfig)
 	QF_VARIANTMAP_KEY_FIELD(QString, qxapitoken, qx, setQx, ApiToken)
 public:
diff --git a/quickevent/app/quickevent/src/application.cpp b/quickevent/app/quickevent/src/application.cpp
index f2b3f3435..5cfb5b7b1 100644
--- a/quickevent/app/quickevent/src/application.cpp
+++ b/quickevent/app/quickevent/src/application.cpp
@@ -68,8 +68,3 @@ Application *Application::instance(bool must_exist)
 	return ret;
 }
 
-QString Application::versionString() const
-{
-	return QCoreApplication::applicationVersion();
-}
-
diff --git a/quickevent/app/quickevent/src/application.h b/quickevent/app/quickevent/src/application.h
index 811f32456..8fbeab0bb 100644
--- a/quickevent/app/quickevent/src/application.h
+++ b/quickevent/app/quickevent/src/application.h
@@ -21,8 +21,6 @@ class Application : public qf::qmlwidgets::framework::Application
 
 	AppCliOptions* cliOptions() {return m_cliOptions;}
 
-	Q_INVOKABLE QString versionString() const;
-
 	Q_SIGNAL void newLogEntry(const qf::core::LogEntryMap &le);
 	void emitNewLogEntry(const qf::core::LogEntryMap &le) { emit newLogEntry(le); }
 private:
diff --git a/quickevent/app/quickevent/src/appversion.h b/quickevent/app/quickevent/src/appversion.h
index 2f3fd2d2b..d4474fcb4 100644
--- a/quickevent/app/quickevent/src/appversion.h
+++ b/quickevent/app/quickevent/src/appversion.h
@@ -1,4 +1,4 @@
 #pragma once
 
-#define APP_VERSION "3.4.2"
+#define APP_VERSION "3.4.3"