diff --git a/src/kdefrontend/DatasetModel.cpp b/src/kdefrontend/DatasetModel.cpp
index 4b6de0916..18dd7b4e0 100644
--- a/src/kdefrontend/DatasetModel.cpp
+++ b/src/kdefrontend/DatasetModel.cpp
@@ -1,201 +1,202 @@
 /***************************************************************************
 	File                 : DatasetModel.cpp
 	Project              : LabPlot
 	Description          : Wrapper class for the collections of datasets
 	--------------------------------------------------------------------
 	Copyright            : (C) 2019 Kovacs Ferencz (kferike98@gmail.com)
 	Copyright            : (C) 2019 by Alexander Semke (alexander.semke@web.de)
 
 ***************************************************************************/
 /***************************************************************************
  *                                                                         *
  *  This program is free software; you can redistribute it and/or modify   *
  *  it under the terms of the GNU General Public License as published by   *
  *  the Free Software Foundation; either version 2 of the License, or      *
  *  (at your option) any later version.                                    *
  *                                                                         *
  *  This program is distributed in the hope that it will be useful,        *
  *  but WITHOUT ANY WARRANTY; without even the implied warranty of         *
  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the          *
  *  GNU General Public License for more details.                           *
  *                                                                         *
  *   You should have received a copy of the GNU General Public License     *
  *   along with this program; if not, write to the Free Software           *
  *   Foundation, Inc., 51 Franklin Street, Fifth Floor,                    *
  *   Boston, MA  02110-1301  USA                                           *
  *                                                                         *
  ***************************************************************************/
 
+#include <QVector>
 #include "DatasetModel.h"
 
 /*!
 \class DatasetModel
 \brief Wrapper class for datasets, and also for their categories and subcategories
 
 \ingroup kdefrontend
 */
 DatasetModel::DatasetModel(const QMap<QString, QMap<QString, QMap<QString, QVector<QString>>>>& datasetsMap) {
 	initCollections(datasetsMap);
 	initCategories(datasetsMap);
 	initSubcategories(datasetsMap);
 	initDatasets(datasetsMap);
 }
 
 DatasetModel::~DatasetModel() {
 
 }
 
 /**
  * @brief Initializes the list of collections.
  */
 void DatasetModel::initCollections(const QMap<QString, QMap<QString, QMap<QString, QVector<QString> > > > & datasetMap) {
 	m_collectionList = datasetMap.keys();
 }
 
 /**
  * @brief Initializes the list of categories.
  */
 void DatasetModel::initCategories(const QMap<QString, QMap<QString, QMap<QString, QVector<QString> > > > & datasetMap) {
 	for(auto i = datasetMap.begin(); i != datasetMap.end(); ++i) {
 		m_categories[i.key()] = i.value().keys();
 
 		for(auto category : i.value().keys()) {
 			if(!m_allCategories.contains(category))
 				m_allCategories.append(category);
 		}
 	}
 }
 
 /**
  * @brief Initializes the list of subcategories.
  */
 void DatasetModel::initSubcategories(const QMap<QString, QMap<QString, QMap<QString, QVector<QString> > > > & datasetMap) {
 	for(auto collection = datasetMap.begin(); collection != datasetMap.end(); ++collection) {
 		const QMap<QString, QMap<QString, QVector<QString> > > collection_ = collection.value();
 
 		for(auto category = collection_.begin(); category != collection_.end(); category++) {
 			m_subcategories[collection.key()][category.key()] = category.value().keys();
 
 			for(auto subcategory: category.value().keys()) {
 				if(!m_allSubcategories[category.key()].contains(subcategory))
 					m_allSubcategories[category.key()].append(subcategory);
 			}
 		}
 	}
 }
 
 /**
  * @brief Initializes the list of datasets.
  */
 void DatasetModel::initDatasets(const QMap<QString, QMap<QString, QMap<QString, QVector<QString> > > >& datasetMap) {
 	for(auto collection = datasetMap.begin(); collection != datasetMap.end(); ++collection) {
 		const QMap<QString, QMap<QString, QVector<QString> > > collection_ = collection.value();
 
 		for(auto category = collection_.begin(); category != collection_.end(); category++) {
 			const QMap<QString, QVector<QString> >category_ = category.value();
 
 			for(auto subcategory = category_.begin(); subcategory != category_.end(); subcategory++) {
 				m_datasets[collection.key()][category.key()][subcategory.key()] = subcategory.value().toList();
 				m_allDatasets[category.key()][subcategory.key()].append(subcategory.value().toList());
 				m_datasetList.append(subcategory.value().toList());
 			}
 		}
 	}
 }
 
 /**
  * @brief Returns the list of categories.
  */
 QStringList DatasetModel::allCategories() {
 	return QVariant(m_allCategories).toStringList();
 }
 
 /**
  * @brief Returns the list of subcategories of a given category.
  * @param category the category the subcategories of which will be returned
  */
 QStringList DatasetModel::allSubcategories(const QString& category) {
 	return QVariant(m_allSubcategories[category]).toStringList();
 }
 
 /**
  * @brief Returns the list of datasets of a given category and subcategory.
  */
 QVariant DatasetModel::allDatasets(const QString& category, const QString& subcategory) {
 	return QVariant(m_allDatasets[category][subcategory]);
 }
 
 /**
  * @brief Returns the list of every dataset.
  */
 QVariant DatasetModel::allDatasetsList() {
 	return QVariant(m_datasetList);
 }
 
 /**
  * @brief Returns the list of categories for a given collection
  */
 QStringList DatasetModel::categories(const QString& collection) {
 	if(!collection.isEmpty())
 		return m_categories[collection];
 	else
 		return allCategories();
 }
 
 /**
  * @brief  Returns the list of subcategories of a given collection and category.
  */
 QStringList DatasetModel::subcategories(const QString& collection, const QString& category) {
 	if(!collection.isEmpty())
 		return m_subcategories[collection][category];
 	else
 		return allSubcategories(category);
 }
 
 /**
  * @brief Returns the list of datasets of a given collection, category and subcategory.
  */
 QStringList DatasetModel::datasets(const QString& collection, const QString& category, const QString& subcategory) {
 	if(!collection.isEmpty())
 		return m_datasets[collection][category][subcategory];
 	else
 		return allDatasets(category, subcategory).toStringList();
 }
 
 /**
  * @brief Returns the number of datasets belonging to the given collection
  */
 int DatasetModel::datasetCount(const QString& collection) {
 	int count = 0;
 	for(const QString& category: categories(collection)) {
 		for(const QString& subcategory: subcategories(collection, category))	{
 			count += datasets(collection, category, subcategory).size();
 		}
 	}
 	return count;
 }
 
 /**
  * @brief Returns the number of datasets belonging to the given collection and category
  */
 int DatasetModel::datasetCount(const QString& collection, const QString& category) {
 	int count = 0;
 	for (const QString& subcategory: subcategories(collection, category))
 		count += datasets(collection, category, subcategory).size();
 
 	return count;
 }
 
 /**
  * @brief Returns the number of datasets belonging to the given collection, category and subcategory
  */
 int DatasetModel::datasetCount(const QString& collection, const QString& category, const QString& subcategory) {
 	return datasets(collection, category, subcategory).size();
 }
 
 /**
  * @brief Returns the list of every collection.
  */
 QStringList DatasetModel::collections() {
 	return m_collectionList;
 }