diff --git a/tabbox/tabboxhandler.cpp b/tabbox/tabboxhandler.cpp
index 594e01c0a..9690e468e 100644
--- a/tabbox/tabboxhandler.cpp
+++ b/tabbox/tabboxhandler.cpp
@@ -1,652 +1,656 @@
 /********************************************************************
  KWin - the KDE window manager
  This file is part of the KDE project.
 
 Copyright (C) 2009 Martin Gräßlin <mgraesslin@kde.org>
 
 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, see <http://www.gnu.org/licenses/>.
 *********************************************************************/
 
 // own
 #include "tabboxhandler.h"
 #include <config-kwin.h>
 #include <kwinglobals.h>
 #include "xcbutils.h"
 // tabbox
 #include "clientmodel.h"
 #include "desktopmodel.h"
 #include "tabboxconfig.h"
 #include "thumbnailitem.h"
 #include "scripting/scripting.h"
 #include "switcheritem.h"
 #include "tabbox_logging.h"
 // Qt
 #include <QKeyEvent>
 #include <QModelIndex>
 #include <QStandardPaths>
 #include <QTimer>
 #include <QQmlContext>
 #include <QQmlComponent>
 #include <QQmlEngine>
 #include <QQuickItem>
 #include <QQuickWindow>
 #include <X11/Xlib.h>
 #include <qpa/qwindowsysteminterface.h>
 // KDE
 #include <KLocalizedString>
 #include <KProcess>
 #include <KPackage/Package>
 #include <KPackage/PackageLoader>
 
 namespace KWin
 {
 namespace TabBox
 {
 
 class TabBoxHandlerPrivate
 {
 public:
     TabBoxHandlerPrivate(TabBoxHandler *q);
 
     ~TabBoxHandlerPrivate();
 
     /**
     * Updates the current highlight window state
     */
     void updateHighlightWindows();
     /**
     * Ends window highlighting
     */
     void endHighlightWindows(bool abort = false);
 
     void show();
     QQuickWindow *window() const;
     SwitcherItem *switcherItem() const;
 
     ClientModel* clientModel() const;
     DesktopModel* desktopModel() const;
 
     TabBoxHandler *q; // public pointer
     // members
     TabBoxConfig config;
     QScopedPointer<QQmlContext> m_qmlContext;
     QScopedPointer<QQmlComponent> m_qmlComponent;
     QObject *m_mainItem;
     QMap<QString, QObject*> m_clientTabBoxes;
     QMap<QString, QObject*> m_desktopTabBoxes;
     ClientModel* m_clientModel;
     DesktopModel* m_desktopModel;
     QModelIndex index;
     /**
     * Indicates if the tabbox is shown.
     */
     bool isShown;
     TabBoxClient *lastRaisedClient, *lastRaisedClientSucc;
     int wheelAngleDelta = 0;
 
 private:
     QObject *createSwitcherItem(bool desktopMode);
 };
 
 TabBoxHandlerPrivate::TabBoxHandlerPrivate(TabBoxHandler *q)
     : m_qmlContext()
     , m_qmlComponent()
     , m_mainItem(nullptr)
 {
     this->q = q;
     isShown = false;
     lastRaisedClient = nullptr;
     lastRaisedClientSucc = nullptr;
     config = TabBoxConfig();
     m_clientModel = new ClientModel(q);
     m_desktopModel = new DesktopModel(q);
 }
 
 TabBoxHandlerPrivate::~TabBoxHandlerPrivate()
 {
     for (auto it = m_clientTabBoxes.constBegin(); it != m_clientTabBoxes.constEnd(); ++it) {
         delete it.value();
     }
     for (auto it = m_desktopTabBoxes.constBegin(); it != m_desktopTabBoxes.constEnd(); ++it) {
         delete it.value();
     }
 }
 
 QQuickWindow *TabBoxHandlerPrivate::window() const
 {
     if (!m_mainItem) {
         return nullptr;
     }
     if (QQuickWindow *w = qobject_cast<QQuickWindow*>(m_mainItem)) {
         return w;
     }
     return m_mainItem->findChild<QQuickWindow*>();
 }
 
 #ifndef KWIN_UNIT_TEST
 SwitcherItem *TabBoxHandlerPrivate::switcherItem() const
 {
     if (!m_mainItem) {
         return nullptr;
     }
     if (SwitcherItem *i = qobject_cast<SwitcherItem*>(m_mainItem)) {
         return i;
     } else if (QQuickWindow *w = qobject_cast<QQuickWindow*>(m_mainItem)) {
         return w->contentItem()->findChild<SwitcherItem*>();
     }
     return m_mainItem->findChild<SwitcherItem*>();
 }
 #endif
 
 ClientModel* TabBoxHandlerPrivate::clientModel() const
 {
     return m_clientModel;
 }
 
 DesktopModel* TabBoxHandlerPrivate::desktopModel() const
 {
     return m_desktopModel;
 }
 
 void TabBoxHandlerPrivate::updateHighlightWindows()
 {
     if (!isShown || config.tabBoxMode() != TabBoxConfig::ClientTabBox)
         return;
 
     TabBoxClient *currentClient = q->client(index);
     QWindow *w = window();
 
     if (q->isKWinCompositing()) {
         if (lastRaisedClient)
             q->elevateClient(lastRaisedClient, w, false);
         lastRaisedClient = currentClient;
         if (currentClient)
             q->elevateClient(currentClient, w, true);
     } else {
         if (lastRaisedClient) {
             q->shadeClient(lastRaisedClient, true);
             if (lastRaisedClientSucc)
                 q->restack(lastRaisedClient, lastRaisedClientSucc);
             // TODO lastRaisedClient->setMinimized( lastRaisedClientWasMinimized );
         }
 
         lastRaisedClient = currentClient;
         if (lastRaisedClient) {
             q->shadeClient(lastRaisedClient, false);
             // TODO if ( (lastRaisedClientWasMinimized = lastRaisedClient->isMinimized()) )
             //         lastRaisedClient->setMinimized( false );
             TabBoxClientList order = q->stackingOrder();
             int succIdx = order.count() + 1;
             for (int i=0; i<order.count(); ++i) {
                 if (order.at(i).data() == lastRaisedClient) {
                     succIdx = i + 1;
                     break;
                 }
             }
             lastRaisedClientSucc = (succIdx < order.count()) ? order.at(succIdx).data() : nullptr;
             q->raiseClient(lastRaisedClient);
         }
     }
 
     if (config.isShowTabBox() && w) {
         q->highlightWindows(currentClient, w);
     } else {
         q->highlightWindows(currentClient);
     }
 }
 
 void TabBoxHandlerPrivate::endHighlightWindows(bool abort)
 {
     TabBoxClient *currentClient = q->client(index);
     if (config.isHighlightWindows() && q->isKWinCompositing()) {
         foreach (const QWeakPointer<TabBoxClient> &clientPointer, q->stackingOrder()) {
             if (QSharedPointer<TabBoxClient> client = clientPointer.toStrongRef())
             if (client != currentClient) // to not mess up with wanted ShadeActive/ShadeHover state
                 q->shadeClient(client.data(), true);
         }
     }
     QWindow *w = window();
     if (currentClient)
         q->elevateClient(currentClient, w, false);
     if (abort && lastRaisedClient && lastRaisedClientSucc)
         q->restack(lastRaisedClient, lastRaisedClientSucc);
     lastRaisedClient = nullptr;
     lastRaisedClientSucc = nullptr;
     // highlight windows
     q->highlightWindows();
 }
 
 #ifndef KWIN_UNIT_TEST
 QObject *TabBoxHandlerPrivate::createSwitcherItem(bool desktopMode)
 {
     // first try look'n'feel package
     QString file = QStandardPaths::locate(QStandardPaths::GenericDataLocation,
                                           QStringLiteral("plasma/look-and-feel/%1/contents/%2")
                                               .arg(config.layoutName())
                                               .arg(desktopMode ? QStringLiteral("desktopswitcher/DesktopSwitcher.qml") : QStringLiteral("windowswitcher/WindowSwitcher.qml")));
     if (file.isNull()) {
         const QString folderName = QLatin1String(KWIN_NAME) + (desktopMode ? QLatin1String("/desktoptabbox/") : QLatin1String("/tabbox/"));
         auto findSwitcher = [this, desktopMode, folderName] {
             const QString type = desktopMode ? QStringLiteral("KWin/DesktopSwitcher") : QStringLiteral("KWin/WindowSwitcher");
             auto offers = KPackage::PackageLoader::self()->findPackages(type,  folderName,
                 [this] (const KPluginMetaData &data) {
                     return data.pluginId().compare(config.layoutName(), Qt::CaseInsensitive) == 0;
                 }
             );
             if (offers.isEmpty()) {
                 // load default
                 offers = KPackage::PackageLoader::self()->findPackages(type,  folderName,
                     [] (const KPluginMetaData &data) {
                         return data.pluginId().compare(QStringLiteral("informative"), Qt::CaseInsensitive) == 0;
                     }
                 );
                 if (offers.isEmpty()) {
                     qCDebug(KWIN_TABBOX) << "could not find default window switcher layout";
                     return KPluginMetaData();
                 }
             }
             return offers.first();
         };
         auto service = findSwitcher();
         if (!service.isValid()) {
             return nullptr;
         }
         if (service.value(QStringLiteral("X-Plasma-API")) != QLatin1String("declarativeappletscript")) {
             qCDebug(KWIN_TABBOX) << "Window Switcher Layout is no declarativeappletscript";
             return nullptr;
         }
         auto findScriptFile = [service, folderName] {
             const QString pluginName = service.pluginId();
             const QString scriptName = service.value(QStringLiteral("X-Plasma-MainScript"));
             return QStandardPaths::locate(QStandardPaths::GenericDataLocation, folderName + pluginName + QLatin1String("/contents/") + scriptName);
         };
         file = findScriptFile();
     }
     if (file.isNull()) {
         qCDebug(KWIN_TABBOX) << "Could not find QML file for window switcher";
         return nullptr;
     }
     m_qmlComponent->loadUrl(QUrl::fromLocalFile(file));
     if (m_qmlComponent->isError()) {
         qCDebug(KWIN_TABBOX) << "Component failed to load: " << m_qmlComponent->errors();
         QStringList args;
         args << QStringLiteral("--passivepopup") << i18n("The Window Switcher installation is broken, resources are missing.\n"
                                             "Contact your distribution about this.") << QStringLiteral("20");
         KProcess::startDetached(QStringLiteral("kdialog"), args);
     } else {
         QObject *object = m_qmlComponent->create(m_qmlContext.data());
         if (desktopMode) {
             m_desktopTabBoxes.insert(config.layoutName(), object);
         } else {
             m_clientTabBoxes.insert(config.layoutName(), object);
         }
         return object;
     }
     return nullptr;
 }
 #endif
 
 void TabBoxHandlerPrivate::show()
 {
 #ifndef KWIN_UNIT_TEST
     if (m_qmlContext.isNull()) {
         qmlRegisterType<SwitcherItem>("org.kde.kwin", 2, 0, "Switcher");
         m_qmlContext.reset(new QQmlContext(Scripting::self()->qmlEngine()));
     }
     if (m_qmlComponent.isNull()) {
         m_qmlComponent.reset(new QQmlComponent(Scripting::self()->qmlEngine()));
     }
     const bool desktopMode = (config.tabBoxMode() == TabBoxConfig::DesktopTabBox);
     auto findMainItem = [this](const QMap<QString, QObject *> &tabBoxes) -> QObject* {
         auto it = tabBoxes.constFind(config.layoutName());
         if (it != tabBoxes.constEnd()) {
             return it.value();
         }
         return nullptr;
     };
     m_mainItem = nullptr;
     m_mainItem = desktopMode ? findMainItem(m_desktopTabBoxes) : findMainItem(m_clientTabBoxes);
     if (!m_mainItem) {
         m_mainItem = createSwitcherItem(desktopMode);
         if (!m_mainItem) {
             return;
         }
     }
     if (SwitcherItem *item = switcherItem()) {
         // In case the model isn't yet set (see below), index will be reset and therefore we
         // need to save the current index row (https://bugs.kde.org/show_bug.cgi?id=333511).
         int indexRow = index.row();
         if (!item->model()) {
             QAbstractItemModel *model = nullptr;
             if (desktopMode) {
                 model = desktopModel();
             } else {
                 model = clientModel();
             }
             item->setModel(model);
         }
         item->setAllDesktops(config.clientDesktopMode() == TabBoxConfig::AllDesktopsClients);
         item->setCurrentIndex(indexRow);
         item->setNoModifierGrab(q->noModifierGrab());
         // everything is prepared, so let's make the whole thing visible
         item->setVisible(true);
     }
     if (QWindow *w = window()) {
         wheelAngleDelta = 0;
         w->installEventFilter(q);
         // pretend to activate the window to enable accessibility notifications
         QWindowSystemInterface::handleWindowActivated(w, Qt::TabFocusReason);
     }
 #endif
 }
 
 /***********************************************
 * TabBoxHandler
 ***********************************************/
 
 TabBoxHandler::TabBoxHandler(QObject *parent)
     : QObject(parent)
 {
     KWin::TabBox::tabBox = this;
     d = new TabBoxHandlerPrivate(this);
 }
 
 TabBoxHandler::~TabBoxHandler()
 {
     delete d;
 }
 
 const KWin::TabBox::TabBoxConfig& TabBoxHandler::config() const
 {
     return d->config;
 }
 
 void TabBoxHandler::setConfig(const TabBoxConfig& config)
 {
     d->config = config;
     emit configChanged();
 }
 
 void TabBoxHandler::show()
 {
     d->isShown = true;
     d->lastRaisedClient = nullptr;
     d->lastRaisedClientSucc = nullptr;
     if (d->config.isShowTabBox()) {
         d->show();
     }
     if (d->config.isHighlightWindows()) {
         if (kwinApp()->x11Connection()) {
             Xcb::sync();
         }
         // TODO this should be
         // QMetaObject::invokeMethod(this, "initHighlightWindows", Qt::QueuedConnection);
         // but we somehow need to cross > 1 event cycle (likely because of queued invocation in the effects)
         // to ensure the EffectWindow is present when updateHighlightWindows, thus elevating the window/tabbox
         QTimer::singleShot(1, this, SLOT(initHighlightWindows()));
     }
 }
 
 void TabBoxHandler::initHighlightWindows()
 {
     if (isKWinCompositing()) {
         foreach (const QWeakPointer<TabBoxClient> &clientPointer, stackingOrder()) {
         if (QSharedPointer<TabBoxClient> client = clientPointer.toStrongRef())
             shadeClient(client.data(), false);
         }
     }
     d->updateHighlightWindows();
 }
 
 void TabBoxHandler::hide(bool abort)
 {
     d->isShown = false;
     if (d->config.isHighlightWindows()) {
         d->endHighlightWindows(abort);
     }
 #ifndef KWIN_UNIT_TEST
     if (SwitcherItem *item = d->switcherItem()) {
         item->setVisible(false);
     }
 #endif
     if (QQuickWindow *w = d->window()) {
         w->hide();
         w->destroy();
     }
     d->m_mainItem = nullptr;
 }
 
 QModelIndex TabBoxHandler::nextPrev(bool forward) const
 {
     QModelIndex ret;
     QAbstractItemModel* model;
     switch(d->config.tabBoxMode()) {
     case TabBoxConfig::ClientTabBox:
         model = d->clientModel();
         break;
     case TabBoxConfig::DesktopTabBox:
         model = d->desktopModel();
         break;
+    default:
+        Q_UNREACHABLE();
     }
     if (forward) {
         int column = d->index.column() + 1;
         int row = d->index.row();
         if (column == model->columnCount()) {
             column = 0;
             row++;
             if (row == model->rowCount())
                 row = 0;
         }
         ret = model->index(row, column);
         if (!ret.isValid())
             ret = model->index(0, 0);
     } else {
         int column = d->index.column() - 1;
         int row = d->index.row();
         if (column < 0) {
             column = model->columnCount() - 1;
             row--;
             if (row < 0)
                 row = model->rowCount() - 1;
         }
         ret = model->index(row, column);
         if (!ret.isValid()) {
             row = model->rowCount() - 1;
             for (int i = model->columnCount() - 1; i >= 0; i--) {
                 ret = model->index(row, i);
                 if (ret.isValid())
                     break;
             }
         }
     }
     if (ret.isValid())
         return ret;
     else
         return d->index;
 }
 
 QModelIndex TabBoxHandler::desktopIndex(int desktop) const
 {
     if (d->config.tabBoxMode() != TabBoxConfig::DesktopTabBox)
         return QModelIndex();
     return d->desktopModel()->desktopIndex(desktop);
 }
 
 QList< int > TabBoxHandler::desktopList() const
 {
     if (d->config.tabBoxMode() != TabBoxConfig::DesktopTabBox)
         return QList< int >();
     return d->desktopModel()->desktopList();
 }
 
 int TabBoxHandler::desktop(const QModelIndex& index) const
 {
     if (!index.isValid() || (d->config.tabBoxMode() != TabBoxConfig::DesktopTabBox))
         return -1;
     QVariant ret = d->desktopModel()->data(index, DesktopModel::DesktopRole);
     if (ret.isValid())
         return ret.toInt();
     else
         return -1;
 }
 
 void TabBoxHandler::setCurrentIndex(const QModelIndex& index)
 {
     if (d->index == index) {
         return;
     }
     if (!index.isValid()) {
         return;
     }
     d->index = index;
     if (d->config.tabBoxMode() == TabBoxConfig::ClientTabBox) {
         if (d->config.isHighlightWindows()) {
             d->updateHighlightWindows();
         }
     }
     emit selectedIndexChanged();
 }
 
 const QModelIndex& TabBoxHandler::currentIndex() const
 {
     return d->index;
 }
 
 void TabBoxHandler::grabbedKeyEvent(QKeyEvent* event) const
 {
     if (!d->m_mainItem || !d->window()) {
         return;
     }
     QCoreApplication::sendEvent(d->window(), event);
 }
 
 bool TabBoxHandler::containsPos(const QPoint& pos) const
 {
     if (!d->m_mainItem) {
         return false;
     }
     QWindow *w = d->window();
     if (w) {
         return w->geometry().contains(pos);
     }
     return false;
 }
 
 QModelIndex TabBoxHandler::index(QWeakPointer<KWin::TabBox::TabBoxClient> client) const
 {
     return d->clientModel()->index(client);
 }
 
 TabBoxClientList TabBoxHandler::clientList() const
 {
     if (d->config.tabBoxMode() != TabBoxConfig::ClientTabBox)
         return TabBoxClientList();
     return d->clientModel()->clientList();
 }
 
 TabBoxClient* TabBoxHandler::client(const QModelIndex& index) const
 {
     if ((!index.isValid()) ||
             (d->config.tabBoxMode() != TabBoxConfig::ClientTabBox))
         return nullptr;
     TabBoxClient* c = static_cast< TabBoxClient* >(
                           d->clientModel()->data(index, ClientModel::ClientRole).value<void *>());
     return c;
 }
 
 void TabBoxHandler::createModel(bool partialReset)
 {
     switch(d->config.tabBoxMode()) {
     case TabBoxConfig::ClientTabBox: {
         d->clientModel()->createClientList(partialReset);
         // TODO: C++11 use lambda function
         bool lastRaised = false;
         bool lastRaisedSucc = false;
         foreach (const QWeakPointer<TabBoxClient> &clientPointer, stackingOrder()) {
             QSharedPointer<TabBoxClient> client = clientPointer.toStrongRef();
             if (!client) {
                 continue;
             }
             if (client.data() == d->lastRaisedClient) {
                 lastRaised = true;
             }
             if (client.data() == d->lastRaisedClientSucc) {
                 lastRaisedSucc = true;
             }
         }
         if (d->lastRaisedClient && !lastRaised)
             d->lastRaisedClient = nullptr;
         if (d->lastRaisedClientSucc && !lastRaisedSucc)
             d->lastRaisedClientSucc = nullptr;
         break;
     }
     case TabBoxConfig::DesktopTabBox:
         d->desktopModel()->createDesktopList();
         break;
     }
 }
 
 QModelIndex TabBoxHandler::first() const
 {
     QAbstractItemModel* model;
     switch(d->config.tabBoxMode()) {
     case TabBoxConfig::ClientTabBox:
         model = d->clientModel();
         break;
     case TabBoxConfig::DesktopTabBox:
         model = d->desktopModel();
         break;
+    default:
+        Q_UNREACHABLE();
     }
     return model->index(0, 0);
 }
 
 bool TabBoxHandler::eventFilter(QObject *watched, QEvent *e)
 {
     if (e->type() == QEvent::Wheel && watched == d->window()) {
         QWheelEvent *event = static_cast<QWheelEvent*>(e);
         // On x11 the delta for vertical scrolling might also be on X for whatever reason
         const int delta = qAbs(event->angleDelta().x()) > qAbs(event->angleDelta().y()) ? event->angleDelta().x() : event->angleDelta().y();
         d->wheelAngleDelta += delta;
         while (d->wheelAngleDelta <= -120) {
             d->wheelAngleDelta += 120;
             const QModelIndex index = nextPrev(true);
             if (index.isValid()) {
                 setCurrentIndex(index);
             }
         }
         while (d->wheelAngleDelta >= 120) {
             d->wheelAngleDelta -= 120;
             const QModelIndex index = nextPrev(false);
             if (index.isValid()) {
                 setCurrentIndex(index);
             }
         }
         return true;
     }
     // pass on
     return QObject::eventFilter(watched, e);
 }
 
 TabBoxHandler* tabBox = nullptr;
 
 TabBoxClient::TabBoxClient()
 {
 }
 
 TabBoxClient::~TabBoxClient()
 {
 }
 
 } // namespace TabBox
 } // namespace KWin