diff --git a/OpenBoard.pro b/OpenBoard.pro
index e0c661ac..8973cae4 100644
--- a/OpenBoard.pro
+++ b/OpenBoard.pro
@@ -40,6 +40,7 @@ QT += webkitwidgets
 QT += multimediawidgets
 QT += printsupport
 QT += core
+QT += concurrent
 
 INCLUDEPATH += src
 
diff --git a/release_scripts/linux/package.sh b/release_scripts/linux/package.sh
index ce2e8f70..25d07230 100755
--- a/release_scripts/linux/package.sh
+++ b/release_scripts/linux/package.sh
@@ -215,6 +215,7 @@ if $BUNDLE_QT; then
 
     notifyProgress "Copying and stripping Qt libraries"
     mkdir -p $QT_LIBRARY_DEST_PATH
+    copyQtLibrary libQt5Concurrent
     copyQtLibrary libQt5Core
     copyQtLibrary libQt5DBus
     copyQtLibrary libQt5Gui
diff --git a/src/core/UBApplicationController.cpp b/src/core/UBApplicationController.cpp
index 27f558c5..27c5d75b 100644
--- a/src/core/UBApplicationController.cpp
+++ b/src/core/UBApplicationController.cpp
@@ -465,6 +465,7 @@ void UBApplicationController::showDesktop(bool dontSwitchFrontProcess)
     if (mMirror)
     {
         QRect rect = qApp->desktop()->screenGeometry(desktopWidgetIndex);
+        rect.moveTo(0, 0);
         mMirror->setSourceRect(rect);
     }
 
diff --git a/src/core/UBDisplayManager.cpp b/src/core/UBDisplayManager.cpp
index f24e9211..4256379d 100644
--- a/src/core/UBDisplayManager.cpp
+++ b/src/core/UBDisplayManager.cpp
@@ -236,7 +236,7 @@ void UBDisplayManager::positionScreens()
 
     if (mDisplayWidget && mDisplayScreenIndex > -1)
     {
-        mDisplayWidget->hide();
+        mDisplayWidget->showNormal();
         mDisplayWidget->setGeometry(mDesktop->screenGeometry(mDisplayScreenIndex));
         UBPlatformUtils::showFullScreen(mDisplayWidget);
     }
diff --git a/src/core/UBDocumentManager.cpp b/src/core/UBDocumentManager.cpp
index 40ab420c..f451e519 100644
--- a/src/core/UBDocumentManager.cpp
+++ b/src/core/UBDocumentManager.cpp
@@ -286,8 +286,6 @@ int UBDocumentManager::addFilesToDocument(UBDocumentProxy* document, QStringList
                         UBGraphicsScene* scene = UBPersistenceManager::persistenceManager()->createDocumentSceneAt(document, pageIndex);
                         importAdaptor->placeImportedItemToScene(scene, page);
                         UBPersistenceManager::persistenceManager()->persistDocumentScene(document, scene, pageIndex);
-                        if (UBApplication::documentController->selectedDocument() == UBApplication::boardController->selectedDocument())
-                            UBApplication::boardController->insertThumbPage(pageIndex);
                     }
 
                     UBPersistenceManager::persistenceManager()->persistDocumentMetadata(document);
diff --git a/src/core/UBPersistenceManager.cpp b/src/core/UBPersistenceManager.cpp
index b2e26cca..e826a7ba 100644
--- a/src/core/UBPersistenceManager.cpp
+++ b/src/core/UBPersistenceManager.cpp
@@ -34,6 +34,7 @@
 #include <QDomDocument>
 #include <QXmlStreamWriter>
 #include <QModelIndex>
+#include <QtConcurrent>
 
 #include "frameworks/UBPlatformUtils.h"
 #include "frameworks/UBFileSystemUtils.h"
@@ -98,7 +99,6 @@ UBPersistenceManager::UBPersistenceManager(QObject *pParent)
     mDocumentTreeStructureModel = new UBDocumentTreeModel(this);
     createDocumentProxiesStructure();
 
-
     emit proxyListChanged();
 }
 
@@ -123,6 +123,50 @@ UBPersistenceManager::~UBPersistenceManager()
 {
 }
 
+void UBPersistenceManager::createDocumentProxiesStructure(const QFileInfoList &contentInfoList, bool interactive)
+{
+    // Create a QFutureWatcher and connect signals and slots.
+    QFutureWatcher<UBDocumentProxy*> futureWatcher;
+    QObject::connect(&futureWatcher, &QFutureWatcher<void>::finished, &mProgress, &QProgressDialog::reset);
+    QObject::connect(&futureWatcher,  &QFutureWatcher<void>::progressRangeChanged, &mProgress, &QProgressDialog::setRange);
+    QObject::connect(&futureWatcher, &QFutureWatcher<void>::progressValueChanged,  &mProgress, &QProgressDialog::setValue);
+
+    // Start the computation.
+    std::function<UBDocumentProxy* (QFileInfo contentInfo)> createDocumentProxyLambda = [=](QFileInfo contentInfo) {
+        return createDocumentProxyStructure(contentInfo);
+    };
+
+    QFuture<UBDocumentProxy*> proxiesFuture = QtConcurrent::mapped(contentInfoList, createDocumentProxyLambda);
+    futureWatcher.setFuture(proxiesFuture);
+
+    // Display the dialog and start the event loop.
+    mProgress.exec();
+
+    futureWatcher.waitForFinished();
+
+    QList<UBDocumentProxy*> proxies = futureWatcher.future().results();
+
+    for (auto&& proxy : qAsConst(proxies))
+    {
+        if (proxy)
+        {
+            QString docGroupName = proxy->metaData(UBSettings::documentGroupName).toString();
+            QModelIndex parentIndex = mDocumentTreeStructureModel->goTo(docGroupName);
+            if (parentIndex.isValid())
+            {
+                if (!interactive)
+                   mDocumentTreeStructureModel->addDocument(proxy, parentIndex);
+                else
+                   processInteractiveReplacementDialog(proxy);
+            }
+            else
+            {
+                qDebug() << "something went wrong";
+            }
+        }
+    }
+}
+
 void UBPersistenceManager::createDocumentProxiesStructure(bool interactive)
 {
     mDocumentRepositoryPath = UBSettings::userDocumentDirectory();
@@ -130,8 +174,13 @@ void UBPersistenceManager::createDocumentProxiesStructure(bool interactive)
     QDir rootDir(mDocumentRepositoryPath);
     rootDir.mkpath(rootDir.path());
 
-    QFileInfoList contentList = rootDir.entryInfoList(QDir::Dirs | QDir::NoDotAndDotDot, QDir::Time | QDir::Reversed);
-    createDocumentProxiesStructure(contentList, interactive);
+    QFileInfoList contentInfoList = rootDir.entryInfoList(QDir::Dirs | QDir::NoDotAndDotDot, QDir::Time | QDir::Reversed);
+
+    mProgress.setWindowFlags(Qt::Window | Qt::WindowTitleHint | Qt::CustomizeWindowHint);
+    mProgress.setLabelText(QString("retrieving all your documents (found %1)").arg(contentInfoList.size()));
+    mProgress.setCancelButton(nullptr);
+
+    createDocumentProxiesStructure(contentInfoList, interactive);
 
     if (QFileInfo(mFoldersXmlStorageName).exists()) {
         QDomDocument xmlDom;
@@ -158,44 +207,36 @@ void UBPersistenceManager::createDocumentProxiesStructure(bool interactive)
     }
 }
 
-void UBPersistenceManager::createDocumentProxiesStructure(const QFileInfoList &contentInfo, bool interactive)
+UBDocumentProxy* UBPersistenceManager::createDocumentProxyStructure(QFileInfo& contentInfo)
 {
-    foreach(QFileInfo path, contentInfo)
-    {
-        QString fullPath = path.absoluteFilePath();
+    QString fullPath = contentInfo.absoluteFilePath();
+    QDir dir(fullPath);
 
-        QDir dir(fullPath);
-
-        if (dir.entryList(QDir::Files | QDir::NoDotAndDotDot).size() > 0)
-        {
-            QMap<QString, QVariant> metadatas = UBMetadataDcSubsetAdaptor::load(fullPath);
-            QString docGroupName = metadatas.value(UBSettings::documentGroupName, QString()).toString();
-            QString docName = metadatas.value(UBSettings::documentName, QString()).toString();
+    if (dir.entryList(QDir::Files | QDir::NoDotAndDotDot).size() > 0)
+    {
+        QMap<QString, QVariant> metadatas = UBMetadataDcSubsetAdaptor::load(fullPath);
+        QString docGroupName = metadatas.value(UBSettings::documentGroupName, QString()).toString();
+        QString docName = metadatas.value(UBSettings::documentName, QString()).toString();
 
-            if (docName.isEmpty()) {
-                qDebug() << "Group name and document name are empty in UBPersistenceManager::createDocumentProxiesStructure()";
-                continue;
-            }
+        if (docName.isEmpty()) {
+            qDebug() << "Group name and document name are empty in UBPersistenceManager::createDocumentProxiesStructure()";
+            return nullptr;
+        }
 
-            QModelIndex parentIndex = mDocumentTreeStructureModel->goTo(docGroupName);
-            if (!parentIndex.isValid()) {
-                return;
-            }
+        UBDocumentProxy* docProxy = new UBDocumentProxy(fullPath); // managed in UBDocumentTreeNode
+        foreach(QString key, metadatas.keys()) {
+            docProxy->setMetaData(key, metadatas.value(key));
+        }
 
-            UBDocumentProxy* docProxy = new UBDocumentProxy(fullPath); // managed in UBDocumentTreeNode
-            foreach(QString key, metadatas.keys()) {
-                docProxy->setMetaData(key, metadatas.value(key));
-            }
+        docProxy->setPageCount(sceneCount(docProxy));
 
-            docProxy->setPageCount(sceneCount(docProxy));
+        docProxy->moveToThread(UBApplication::instance()->thread());
 
-            if (!interactive)
-                mDocumentTreeStructureModel->addDocument(docProxy, parentIndex);
-            else
-                processInteractiveReplacementDialog(docProxy);
-        }
+        return docProxy;
     }
-}
+
+    return nullptr;
+};
 
 QDialog::DialogCode UBPersistenceManager::processInteractiveReplacementDialog(UBDocumentProxy *pProxy)
 {
diff --git a/src/core/UBPersistenceManager.h b/src/core/UBPersistenceManager.h
index 8a1462ce..18353b0b 100644
--- a/src/core/UBPersistenceManager.h
+++ b/src/core/UBPersistenceManager.h
@@ -131,7 +131,8 @@ class UBPersistenceManager : public QObject
         bool addDirectoryContentToDocument(const QString& documentRootFolder, UBDocumentProxy* pDocument);
 
         void createDocumentProxiesStructure(bool interactive = false);
-        void createDocumentProxiesStructure(const QFileInfoList &contentInfo, bool interactive = false);
+        void createDocumentProxiesStructure(const QFileInfoList &contentInfoList, bool interactive = false);
+        UBDocumentProxy* createDocumentProxyStructure(QFileInfo &contentInfo);
         QDialog::DialogCode processInteractiveReplacementDialog(UBDocumentProxy *pProxy);
 
         QStringList documentSubDirectories()
@@ -187,6 +188,8 @@ private:
         bool mHasPurgedDocuments;
         QString mDocumentRepositoryPath;
         QString mFoldersXmlStorageName;
+        QProgressDialog mProgress;
+        QFutureWatcher<void> futureWatcher;
 
     private slots:
         void documentRepositoryChanged(const QString& path);
diff --git a/src/desktop/UBCustomCaptureWindow.cpp b/src/desktop/UBCustomCaptureWindow.cpp
index dc26abad..1a319738 100644
--- a/src/desktop/UBCustomCaptureWindow.cpp
+++ b/src/desktop/UBCustomCaptureWindow.cpp
@@ -79,6 +79,8 @@ int UBCustomCaptureWindow::execute(const QPixmap &pScreenPixmap)
 
     QDesktopWidget *desktop = QApplication::desktop();
     int currentScreen = desktop->screenNumber(QCursor::pos());
+    // necessary so that changing geometry really affects the widget
+    showNormal();
     setGeometry(desktop->screenGeometry(currentScreen));
     this->show();
     setWindowOpacity(1.0);
diff --git a/src/desktop/UBDesktopAnnotationController.cpp b/src/desktop/UBDesktopAnnotationController.cpp
index 138d0fb4..f63560e6 100644
--- a/src/desktop/UBDesktopAnnotationController.cpp
+++ b/src/desktop/UBDesktopAnnotationController.cpp
@@ -516,6 +516,7 @@ QPixmap UBDesktopAnnotationController::getScreenPixmap()
     QScreen * screen = UBApplication::controlScreen();
 
     QRect rect = desktop->screenGeometry(QCursor::pos());
+    rect.moveTo(0, 0);
 
     return screen->grabWindow(desktop->effectiveWinId(),
                               rect.x(), rect.y(), rect.width(), rect.height());
@@ -556,7 +557,7 @@ void UBDesktopAnnotationController::penActionPressed()
 
     // Check if the mouse cursor is on the little arrow
     QPoint cursorPos = QCursor::pos();
-    QPoint palettePos = mDesktopPalette->pos();
+    QPoint palettePos = mDesktopPalette->mapToGlobal(QPoint(0, 0));  // global coordinates of palette
     QPoint buttonPos = mDesktopPalette->buttonPos(UBApplication::mainWindow->actionPen);
 
     int iX = cursorPos.x() - (palettePos.x() + buttonPos.x());    // x position of the cursor in the palette
@@ -610,7 +611,7 @@ void UBDesktopAnnotationController::eraserActionPressed()
 
     // Check if the mouse cursor is on the little arrow
     QPoint cursorPos = QCursor::pos();
-    QPoint palettePos = mDesktopPalette->pos();
+    QPoint palettePos = mDesktopPalette->mapToGlobal(QPoint(0, 0));
     QPoint buttonPos = mDesktopPalette->buttonPos(UBApplication::mainWindow->actionEraser);
 
     int iX = cursorPos.x() - (palettePos.x() + buttonPos.x());    // x position of the cursor in the palette
@@ -665,7 +666,7 @@ void UBDesktopAnnotationController::markerActionPressed()
 
     // Check if the mouse cursor is on the little arrow
     QPoint cursorPos = QCursor::pos();
-    QPoint palettePos = mDesktopPalette->pos();
+    QPoint palettePos = mDesktopPalette->mapToGlobal(QPoint(0, 0));
     QPoint buttonPos = mDesktopPalette->buttonPos(UBApplication::mainWindow->actionMarker);
 
     int iX = cursorPos.x() - (palettePos.x() + buttonPos.x());    // x position of the cursor in the palette
@@ -967,7 +968,7 @@ void UBDesktopAnnotationController::updateMask(bool bTransparent)
         p.setPen(Qt::red);
         p.setBrush(QBrush(Qt::red));
 
-        p.drawRect(mTransparentDrawingView->geometry().x(), mTransparentDrawingView->geometry().y(), mTransparentDrawingView->width(), mTransparentDrawingView->height());
+        p.drawRect(0, 0, mTransparentDrawingView->width(), mTransparentDrawingView->height());
         p.end();
 
         mTransparentDrawingView->setMask(mMask.mask());
diff --git a/src/document/UBDocumentController.cpp b/src/document/UBDocumentController.cpp
index 24371875..e76c7ecd 100644
--- a/src/document/UBDocumentController.cpp
+++ b/src/document/UBDocumentController.cpp
@@ -2393,8 +2393,11 @@ void UBDocumentController::duplicateSelectedItem()
             int sceneCount = selectedSceneIndexes.count();
             showMessage(tr("duplicated %1 page","duplicated %1 pages",sceneCount).arg(sceneCount), false);
 
-            mBoardController->setActiveDocumentScene(selectedThumbnail);
-            mBoardController->reloadThumbnails();
+            if (selectedDocument() == mBoardController->selectedDocument())
+            {
+                mBoardController->setActiveDocumentScene(selectedThumbnail);
+                mBoardController->reloadThumbnails();
+            }
         }
     }
     else
@@ -2999,6 +3002,8 @@ void UBDocumentController::addFolderOfImages()
                 document->setMetaData(UBSettings::documentUpdatedAt, UBStringUtils::toUtcIsoDateTime(QDateTime::currentDateTime()));
                 UBMetadataDcSubsetAdaptor::persist(document);
                 reloadThumbnails();
+                if (selectedDocument() == UBApplication::boardController->selectedDocument())
+                    UBApplication::boardController->reloadThumbnails();
             }
         }
     }
@@ -3012,11 +3017,6 @@ void UBDocumentController::addFileToDocument()
     if (document)
     {
          addFileToDocument(document);
-         reloadThumbnails();
-         if (UBApplication::boardController->selectedDocument() == selectedDocument())
-         {
-             UBApplication::boardController->reloadThumbnails();
-         }
     }
 }
 
@@ -3050,6 +3050,8 @@ bool UBDocumentController::addFileToDocument(UBDocumentProxy* document)
             document->setMetaData(UBSettings::documentUpdatedAt, UBStringUtils::toUtcIsoDateTime(QDateTime::currentDateTime()));
             UBMetadataDcSubsetAdaptor::persist(document);
             reloadThumbnails();
+            if (selectedDocument() == UBApplication::boardController->selectedDocument())
+                UBApplication::boardController->reloadThumbnails();
         }
         else
         {
@@ -3328,6 +3330,8 @@ void UBDocumentController::addImages()
                 document->setMetaData(UBSettings::documentUpdatedAt, UBStringUtils::toUtcIsoDateTime(QDateTime::currentDateTime()));
                 UBMetadataDcSubsetAdaptor::persist(document);
                 reloadThumbnails();
+                if (selectedDocument() == UBApplication::boardController->selectedDocument())
+                    UBApplication::boardController->reloadThumbnails();
             }
         }
     }
@@ -3777,6 +3781,8 @@ void UBDocumentController:: refreshDocumentThumbnailsView(UBDocumentContainer* s
                                                        , QList<QUrl>()
                                                        , QStringList()
                                                        , UBApplication::mimeTypeUniboardPage);
+
+        QApplication::restoreOverrideCursor();
         return;
     }
 
diff --git a/src/frameworks/UBFileSystemUtils.cpp b/src/frameworks/UBFileSystemUtils.cpp
index 6c5ae6d6..42915957 100644
--- a/src/frameworks/UBFileSystemUtils.cpp
+++ b/src/frameworks/UBFileSystemUtils.cpp
@@ -105,6 +105,11 @@ bool UBFileSystemUtils::copyFile(const QString &source, const QString &destinati
         if  (QFileInfo(normalizedDestination).isFile() && overwrite) {
             QFile::remove(normalizedDestination);
         }
+        else
+        {
+            if (!overwrite)
+                return true; // don't try to copy an existing file if overwrite is false
+        }
     } else {
         normalizedDestination = normalizedDestination.replace(QString("\\"), QString("/"));
         int pos = normalizedDestination.lastIndexOf("/");
@@ -300,7 +305,7 @@ bool UBFileSystemUtils::copyDir(const QString& pSourceDirPath, const QString& pT
         {
             if (dirContent.isDir())
             {
-                successSoFar = copyDir(pSourceDirPath + "/" + dirContent.fileName(), pTargetDirPath + "/" + dirContent.fileName());
+                successSoFar = copyDir(pSourceDirPath + "/" + dirContent.fileName(), pTargetDirPath + "/" + dirContent.fileName(), overwite);
             }
             else
             {
diff --git a/src/gui/UBBoardThumbnailsView.cpp b/src/gui/UBBoardThumbnailsView.cpp
index fe10ecca..a6f9ba4e 100644
--- a/src/gui/UBBoardThumbnailsView.cpp
+++ b/src/gui/UBBoardThumbnailsView.cpp
@@ -307,7 +307,7 @@ void UBBoardThumbnailsView::dragMoveEvent(QDragMoveEvent *event)
             {
                 y = item->pos().y() - UBSettings::thumbnailSpacing / 2;
                 if (mDropBar->y() != y)
-                    mDropBar->setRect(QRectF(item->pos().x(), y, mThumbnailWidth-verticalScrollBar()->width(), 3));
+                    mDropBar->setRect(QRectF(item->pos().x(), y, (item->boundingRect().width()-verticalScrollBar()->width())*scale, 3));
             }
         }
         else
@@ -316,7 +316,7 @@ void UBBoardThumbnailsView::dragMoveEvent(QDragMoveEvent *event)
             {
                 y = item->pos().y() + item->boundingRect().height() * scale + UBSettings::thumbnailSpacing / 2;
                 if (mDropBar->y() != y)
-                    mDropBar->setRect(QRectF(item->pos().x(), y, mThumbnailWidth-verticalScrollBar()->width(), 3));
+                    mDropBar->setRect(QRectF(item->pos().x(), y, (item->boundingRect().width()-verticalScrollBar()->width())*scale, 3));
             }
         }
     }