qmldesigner: make DesignerSettings thread save

Change-Id: I07074b35456533e9729644ef3647803d477bd6f1
Reviewed-by: Marco Bubke <marco.bubke@qt.io>

27 files changed, 107 insertions, 111 deletions

diff --git a/src/plugins/qmldesigner/components/assetslibrary/assetslibrarymodel.cpp b/src/plugins/qmldesigner/components/assetslibrary/assetslibrarymodel.cpp
index 719406ea1a..18967a5fe1 100644
--- a/src/plugins/qmldesigner/components/assetslibrary/assetslibrarymodel.cpp
+++ b/src/plugins/qmldesigner/components/assetslibrary/assetslibrarymodel.cpp
@@ -109,7 +109,7 @@ void AssetsLibraryModel::toggleExpandAll(bool expand)
 
 void AssetsLibraryModel::deleteFiles(const QStringList &filePaths)
 {
-    bool askBeforeDelete = DesignerSettings::getValue(
+    bool askBeforeDelete = QmlDesignerPlugin::settings().value(
                 DesignerSettingsKey::ASK_BEFORE_DELETING_ASSET).toBool();
     bool assetDelete = true;
 
@@ -129,7 +129,7 @@ void AssetsLibraryModel::deleteFiles(const QStringList &filePaths)
             assetDelete = false;
 
         if (cb.isChecked())
-            DesignerSettings::setValue(DesignerSettingsKey::ASK_BEFORE_DELETING_ASSET, false);
+            QmlDesignerPlugin::settings().insert(DesignerSettingsKey::ASK_BEFORE_DELETING_ASSET, false);
     }
 
     if (assetDelete) {
diff --git a/src/plugins/qmldesigner/components/componentcore/crumblebar.cpp b/src/plugins/qmldesigner/components/componentcore/crumblebar.cpp
index 82032b3fc2..a9b52c13b6 100644
--- a/src/plugins/qmldesigner/components/componentcore/crumblebar.cpp
+++ b/src/plugins/qmldesigner/components/componentcore/crumblebar.cpp
@@ -145,7 +145,7 @@ Utils::CrumblePath *CrumbleBar::crumblePath()
 bool CrumbleBar::showSaveDialog()
 {
     bool canceled = false;
-    bool alwaysSave = DesignerSettings::getValue(DesignerSettingsKey::ALWAYS_SAVE_IN_CRUMBLEBAR).toBool();
+    bool alwaysSave = QmlDesignerPlugin::settings().value(DesignerSettingsKey::ALWAYS_SAVE_IN_CRUMBLEBAR).toBool();
     if (alwaysSave) {
         Core::DocumentManager::saveModifiedDocumentSilently(currentDesignDocument()->editor()->document());
     } else {
@@ -155,7 +155,7 @@ bool CrumbleBar::showSaveDialog()
                                                     tr("Always save when leaving subcomponent"),
                                                     &alwaysSave);
 
-        DesignerSettings::setValue(DesignerSettingsKey::ALWAYS_SAVE_IN_CRUMBLEBAR, alwaysSave);
+        QmlDesignerPlugin::settings().insert(DesignerSettingsKey::ALWAYS_SAVE_IN_CRUMBLEBAR, alwaysSave);
     }
     return !canceled;
 }
diff --git a/src/plugins/qmldesigner/components/connectioneditor/connectionviewwidget.cpp b/src/plugins/qmldesigner/components/connectioneditor/connectionviewwidget.cpp
index ae5eee7590..bed52cc7a7 100644
--- a/src/plugins/qmldesigner/components/connectioneditor/connectionviewwidget.cpp
+++ b/src/plugins/qmldesigner/components/connectioneditor/connectionviewwidget.cpp
@@ -96,8 +96,6 @@ ConnectionViewWidget::ConnectionViewWidget(QWidget *parent) :
     for (auto toolButton : buttons)
         ui->toolBar->addWidget(toolButton);
 
-    auto settings = QmlDesignerPlugin::instance()->settings();
-
     if (!QmlProjectManager::QmlProject::isQtDesignStudio())
         ui->tabBar->addTab(tr("Backends", "Title of dynamic properties view"));
 
diff --git a/src/plugins/qmldesigner/components/debugview/debugview.cpp b/src/plugins/qmldesigner/components/debugview/debugview.cpp
index c32edec724..2d3b232e51 100644
--- a/src/plugins/qmldesigner/components/debugview/debugview.cpp
+++ b/src/plugins/qmldesigner/components/debugview/debugview.cpp
@@ -44,13 +44,13 @@ const QString lineBreak = QStringLiteral("<br>");
 
 bool isDebugViewEnabled()
 {
-    return QmlDesigner::DesignerSettings::getValue(
+    return QmlDesigner::QmlDesignerPlugin::settings().value(
         QmlDesigner::DesignerSettingsKey::ENABLE_DEBUGVIEW).toBool();
 }
 
 bool isDebugViewShown()
 {
-    return QmlDesigner::DesignerSettings::getValue(
+    return QmlDesigner::QmlDesignerPlugin::settings().value(
         QmlDesigner::DesignerSettingsKey::SHOW_DEBUGVIEW).toBool();
 }
 
diff --git a/src/plugins/qmldesigner/components/debugview/debugviewwidget.cpp b/src/plugins/qmldesigner/components/debugview/debugviewwidget.cpp
index e7c2ceac7b..766af4985c 100644
--- a/src/plugins/qmldesigner/components/debugview/debugviewwidget.cpp
+++ b/src/plugins/qmldesigner/components/debugview/debugviewwidget.cpp
@@ -100,7 +100,7 @@ void DebugViewWidget::setDebugViewEnabled(bool b)
 
 void DebugViewWidget::enabledCheckBoxToggled(bool b)
 {
-    DesignerSettings::setValue(DesignerSettingsKey::WARNING_FOR_FEATURES_IN_DESIGNER, b);
+    QmlDesignerPlugin::settings().insert(DesignerSettingsKey::WARNING_FOR_FEATURES_IN_DESIGNER, b);
 }
 
 } //namespace Internal
diff --git a/src/plugins/qmldesigner/components/edit3d/edit3dview.cpp b/src/plugins/qmldesigner/components/edit3d/edit3dview.cpp
index b727df8491..5db622eb7b 100644
--- a/src/plugins/qmldesigner/components/edit3d/edit3dview.cpp
+++ b/src/plugins/qmldesigner/components/edit3d/edit3dview.cpp
@@ -535,7 +535,7 @@ void Edit3DView::createEdit3DActions()
         m_particlesRestartAction->action()->setEnabled(particlemode);
         if (m_seeker)
             m_seeker->setEnabled(false);
-        QmlDesigner::DesignerSettings::setValue("particleMode", particlemode);
+        QmlDesignerPlugin::settings().insert("particleMode", particlemode);
         setCurrentStateNode(rootModelNode());
         resetPuppet();
     };
diff --git a/src/plugins/qmldesigner/components/edit3d/edit3dviewconfig.h b/src/plugins/qmldesigner/components/edit3d/edit3dviewconfig.h
index 8e4081176a..76cfdacdce 100644
--- a/src/plugins/qmldesigner/components/edit3d/edit3dviewconfig.h
+++ b/src/plugins/qmldesigner/components/edit3d/edit3dviewconfig.h
@@ -40,7 +40,7 @@ class Edit3DViewConfig
 public:
     static QList<QColor> load(const char key[])
     {
-        QVariant var = DesignerSettings::getValue(key);
+        QVariant var = QmlDesignerPlugin::settings().value(key);
 
         if (!var.isValid())
             return {};
@@ -91,7 +91,7 @@ private:
 
     static void saveVariant(const QByteArray &key, const QVariant &colorConfig)
     {
-        DesignerSettings::setValue(key, colorConfig);
+        QmlDesignerPlugin::settings().insert(key, colorConfig);
     }
 };
 
diff --git a/src/plugins/qmldesigner/components/formeditor/formeditorscene.cpp b/src/plugins/qmldesigner/components/formeditor/formeditorscene.cpp
index 5beb60a98e..7b9e27c7e1 100644
--- a/src/plugins/qmldesigner/components/formeditor/formeditorscene.cpp
+++ b/src/plugins/qmldesigner/components/formeditor/formeditorscene.cpp
@@ -95,12 +95,12 @@ FormEditorItem* FormEditorScene::itemForQmlItemNode(const QmlItemNode &qmlItemNo
 
 double FormEditorScene::canvasWidth() const
 {
-    return DesignerSettings::getValue(DesignerSettingsKey::CANVASWIDTH).toDouble();
+    return QmlDesignerPlugin::settings().value(DesignerSettingsKey::CANVASWIDTH).toDouble();
 }
 
 double FormEditorScene::canvasHeight() const
 {
-    return DesignerSettings::getValue(DesignerSettingsKey::CANVASHEIGHT).toDouble();
+    return QmlDesignerPlugin::settings().value(DesignerSettingsKey::CANVASHEIGHT).toDouble();
 }
 
 QList<FormEditorItem*> FormEditorScene::itemsForQmlItemNodes(const QList<QmlItemNode> &nodeList) const
diff --git a/src/plugins/qmldesigner/components/formeditor/formeditorview.cpp b/src/plugins/qmldesigner/components/formeditor/formeditorview.cpp
index 42ecfc0679..c3f697d5c6 100644
--- a/src/plugins/qmldesigner/components/formeditor/formeditorview.cpp
+++ b/src/plugins/qmldesigner/components/formeditor/formeditorview.cpp
@@ -36,6 +36,7 @@
 #include "formeditorscene.h"
 #include "abstractcustomtool.h"
 
+#include <qmldesignerplugin.h>
 #include <bindingproperty.h>
 #include <variantproperty.h>
 #include <designersettings.h>
@@ -685,8 +686,8 @@ void FormEditorView::instancesCompleted(const QVector<ModelNode> &completedNodeL
 void FormEditorView::instanceInformationsChanged(const QMultiHash<ModelNode, InformationName> &informationChangedHash)
 {
     QList<FormEditorItem*> changedItems;
-    const int rootElementInitWidth = DesignerSettings::getValue(DesignerSettingsKey::ROOT_ELEMENT_INIT_WIDTH).toInt();
-    const int rootElementInitHeight = DesignerSettings::getValue(DesignerSettingsKey::ROOT_ELEMENT_INIT_HEIGHT).toInt();
+    const int rootElementInitWidth = QmlDesignerPlugin::settings().value(DesignerSettingsKey::ROOT_ELEMENT_INIT_WIDTH).toInt();
+    const int rootElementInitHeight = QmlDesignerPlugin::settings().value(DesignerSettingsKey::ROOT_ELEMENT_INIT_HEIGHT).toInt();
 
     QList<ModelNode> informationChangedNodes = Utils::filtered(informationChangedHash.keys(), [](const ModelNode &node) {
         return QmlItemNode::isValidQmlItemNode(node);
diff --git a/src/plugins/qmldesigner/components/formeditor/formeditorwidget.cpp b/src/plugins/qmldesigner/components/formeditor/formeditorwidget.cpp
index 6991c56141..ff52e244ca 100644
--- a/src/plugins/qmldesigner/components/formeditor/formeditorwidget.cpp
+++ b/src/plugins/qmldesigner/components/formeditor/formeditorwidget.cpp
@@ -479,12 +479,12 @@ ToolBox *FormEditorWidget::toolBox() const
 
 double FormEditorWidget::spacing() const
 {
-    return DesignerSettings::getValue(DesignerSettingsKey::ITEMSPACING).toDouble();
+    return QmlDesignerPlugin::settings().value(DesignerSettingsKey::ITEMSPACING).toDouble();
 }
 
 double FormEditorWidget::containerPadding() const
 {
-    return DesignerSettings::getValue(DesignerSettingsKey::CONTAINERPADDING).toDouble();
+    return QmlDesignerPlugin::settings().value(DesignerSettingsKey::CONTAINERPADDING).toDouble();
 }
 
 void FormEditorWidget::contextHelp(const Core::IContext::HelpCallback &callback) const
diff --git a/src/plugins/qmldesigner/components/itemlibrary/itemlibrarywidget.cpp b/src/plugins/qmldesigner/components/itemlibrary/itemlibrarywidget.cpp
index e1911036b5..1e4a9d232f 100644
--- a/src/plugins/qmldesigner/components/itemlibrary/itemlibrarywidget.cpp
+++ b/src/plugins/qmldesigner/components/itemlibrary/itemlibrarywidget.cpp
@@ -285,7 +285,7 @@ void ItemLibraryWidget::goIntoComponent(const QString &source)
 
 void ItemLibraryWidget::delayedUpdateModel()
 {
-    static bool disableTimer = DesignerSettings::getValue(DesignerSettingsKey::DISABLE_ITEM_LIBRARY_UPDATE_TIMER).toBool();
+    static bool disableTimer = QmlDesignerPlugin::settings().value(DesignerSettingsKey::DISABLE_ITEM_LIBRARY_UPDATE_TIMER).toBool();
     if (disableTimer)
         updateModel();
     else
diff --git a/src/plugins/qmldesigner/components/navigator/navigatorview.cpp b/src/plugins/qmldesigner/components/navigator/navigatorview.cpp
index cc3934b628..64f7d05602 100644
--- a/src/plugins/qmldesigner/components/navigator/navigatorview.cpp
+++ b/src/plugins/qmldesigner/components/navigator/navigatorview.cpp
@@ -158,10 +158,10 @@ void NavigatorView::modelAttached(Model *model)
 
     QTimer::singleShot(0, this, [this, treeView]() {
         m_currentModelInterface->setFilter(
-                    DesignerSettings::getValue(DesignerSettingsKey::NAVIGATOR_SHOW_ONLY_VISIBLE_ITEMS).toBool());
+                    QmlDesignerPlugin::settings().value(DesignerSettingsKey::NAVIGATOR_SHOW_ONLY_VISIBLE_ITEMS).toBool());
 
         m_currentModelInterface->setOrder(
-                    DesignerSettings::getValue(DesignerSettingsKey::NAVIGATOR_REVERSE_ITEM_ORDER).toBool());
+                    QmlDesignerPlugin::settings().value(DesignerSettingsKey::NAVIGATOR_REVERSE_ITEM_ORDER).toBool());
 
         // Expand everything to begin with to ensure model node to index cache is populated
         treeView->expandAll();
@@ -528,7 +528,7 @@ void NavigatorView::rightButtonClicked()
         return; //Semantics are unclear for multi selection.
 
     bool blocked = blockSelectionChangedSignal(true);
-    bool reverse = DesignerSettings::getValue(DesignerSettingsKey::NAVIGATOR_REVERSE_ITEM_ORDER).toBool();
+    bool reverse = QmlDesignerPlugin::settings().value(DesignerSettingsKey::NAVIGATOR_REVERSE_ITEM_ORDER).toBool();
 
     for (const ModelNode &node : selectedModelNodes()) {
         if (!node.isRootNode() && node.parentProperty().isNodeListProperty() && node.parentProperty().count() > 1) {
@@ -568,7 +568,7 @@ void NavigatorView::rightButtonClicked()
 void NavigatorView::upButtonClicked()
 {
     bool blocked = blockSelectionChangedSignal(true);
-    bool reverse = DesignerSettings::getValue(DesignerSettingsKey::NAVIGATOR_REVERSE_ITEM_ORDER).toBool();
+    bool reverse = QmlDesignerPlugin::settings().value(DesignerSettingsKey::NAVIGATOR_REVERSE_ITEM_ORDER).toBool();
 
     if (reverse)
         moveNodesDown(selectedModelNodes());
@@ -582,7 +582,7 @@ void NavigatorView::upButtonClicked()
 void NavigatorView::downButtonClicked()
 {
     bool blocked = blockSelectionChangedSignal(true);
-    bool reverse = DesignerSettings::getValue(DesignerSettingsKey::NAVIGATOR_REVERSE_ITEM_ORDER).toBool();
+    bool reverse = QmlDesignerPlugin::settings().value(DesignerSettingsKey::NAVIGATOR_REVERSE_ITEM_ORDER).toBool();
 
     if (reverse)
         moveNodesUp(selectedModelNodes());
@@ -597,14 +597,14 @@ void NavigatorView::filterToggled(bool flag)
 {
     m_currentModelInterface->setFilter(flag);
     treeWidget()->expandAll();
-    DesignerSettings::setValue(DesignerSettingsKey::NAVIGATOR_SHOW_ONLY_VISIBLE_ITEMS, flag);
+    QmlDesignerPlugin::settings().insert(DesignerSettingsKey::NAVIGATOR_SHOW_ONLY_VISIBLE_ITEMS, flag);
 }
 
 void NavigatorView::reverseOrderToggled(bool flag)
 {
     m_currentModelInterface->setOrder(flag);
     treeWidget()->expandAll();
-    DesignerSettings::setValue(DesignerSettingsKey::NAVIGATOR_REVERSE_ITEM_ORDER, flag);
+    QmlDesignerPlugin::settings().insert(DesignerSettingsKey::NAVIGATOR_REVERSE_ITEM_ORDER, flag);
 }
 
 void NavigatorView::textFilterChanged(const QString &text)
diff --git a/src/plugins/qmldesigner/components/navigator/navigatorwidget.cpp b/src/plugins/qmldesigner/components/navigator/navigatorwidget.cpp
index d43f4a1fe6..f3ccd491c8 100644
--- a/src/plugins/qmldesigner/components/navigator/navigatorwidget.cpp
+++ b/src/plugins/qmldesigner/components/navigator/navigatorwidget.cpp
@@ -138,7 +138,7 @@ QList<QToolButton *> NavigatorWidget::createToolBarWidgets()
     auto filterAction = new QAction(tr("Show Only Visible Components"), nullptr);
     filterAction->setCheckable(true);
 
-    bool filterFlag = DesignerSettings::getValue(DesignerSettingsKey::NAVIGATOR_SHOW_ONLY_VISIBLE_ITEMS).toBool();
+    bool filterFlag = QmlDesignerPlugin::settings().value(DesignerSettingsKey::NAVIGATOR_SHOW_ONLY_VISIBLE_ITEMS).toBool();
     filterAction->setChecked(filterFlag);
 
     connect(filterAction, &QAction::toggled, this, &NavigatorWidget::filterToggled);
@@ -147,7 +147,7 @@ QList<QToolButton *> NavigatorWidget::createToolBarWidgets()
     auto reverseAction = new QAction(tr("Reverse Component Order"), nullptr);
     reverseAction->setCheckable(true);
 
-    bool reverseFlag = DesignerSettings::getValue(DesignerSettingsKey::NAVIGATOR_REVERSE_ITEM_ORDER).toBool();
+    bool reverseFlag = QmlDesignerPlugin::settings().value(DesignerSettingsKey::NAVIGATOR_REVERSE_ITEM_ORDER).toBool();
     reverseAction->setChecked(reverseFlag);
 
     connect(reverseAction, &QAction::toggled, this, &NavigatorWidget::reverseOrderToggled);
diff --git a/src/plugins/qmldesigner/components/propertyeditor/colorpalettebackend.h b/src/plugins/qmldesigner/components/propertyeditor/colorpalettebackend.h
index 2042b30802..7266f89856 100644
--- a/src/plugins/qmldesigner/components/propertyeditor/colorpalettebackend.h
+++ b/src/plugins/qmldesigner/components/propertyeditor/colorpalettebackend.h
@@ -35,6 +35,7 @@
 #include <QPixmap>
 
 #include "designersettings.h"
+#include <qmldesignerplugin.h>
 #include <coreplugin/icore.h>
 
 namespace QmlDesigner {
@@ -59,7 +60,7 @@ struct Palette
 
     bool read()
     {
-        QStringList data = QmlDesigner::DesignerSettings::getValue(m_settingsKey).toStringList();
+        QStringList data = QmlDesignerPlugin::settings().value(m_settingsKey).toStringList();
         if (data.isEmpty())
             return false;
 
@@ -71,7 +72,7 @@ struct Palette
 
     void write() const
     {
-        QmlDesigner::DesignerSettings::setValue(m_settingsKey, m_colors);
+        QmlDesignerPlugin::settings().insert(m_settingsKey, m_colors);
     }
 
     QByteArray m_settingsKey;
diff --git a/src/plugins/qmldesigner/components/texteditor/texteditorview.cpp b/src/plugins/qmldesigner/components/texteditor/texteditorview.cpp
index 30375f9fc0..6ed1d88c00 100644
--- a/src/plugins/qmldesigner/components/texteditor/texteditorview.cpp
+++ b/src/plugins/qmldesigner/components/texteditor/texteditorview.cpp
@@ -266,7 +266,7 @@ void TextEditorView::reformatFile()
 
     // Reformat document if we have a .ui.qml file
     if (document && document->filePath().toString().endsWith(".ui.qml")
-                 && DesignerSettings::getValue(DesignerSettingsKey::REFORMAT_UI_QML_FILES).toBool()) {
+                 && QmlDesignerPlugin::settings().value(DesignerSettingsKey::REFORMAT_UI_QML_FILES).toBool()) {
 
         QmlJS::Document::Ptr currentDocument(document->semanticInfo().document);
         QmlJS::Snapshot snapshot = QmlJS::ModelManagerInterface::instance()->snapshot();
diff --git a/src/plugins/qmldesigner/designercore/exceptions/exception.cpp b/src/plugins/qmldesigner/designercore/exceptions/exception.cpp
index a3a9806f7e..8216117319 100644
--- a/src/plugins/qmldesigner/designercore/exceptions/exception.cpp
+++ b/src/plugins/qmldesigner/designercore/exceptions/exception.cpp
@@ -91,8 +91,8 @@ bool Exception::shouldAssert()
 bool Exception::warnAboutException()
 {
 #ifndef QMLDESIGNER_TEST
-    static bool warnException = !QmlDesignerPlugin::instance()->settings().value(
-                DesignerSettingsKey::ENABLE_MODEL_EXCEPTION_OUTPUT).toBool();
+    static bool warnException = !QmlDesignerPlugin::settings().value(
+        DesignerSettingsKey::ENABLE_MODEL_EXCEPTION_OUTPUT).toBool();
     return warnException;
 #else
     return true;
diff --git a/src/plugins/qmldesigner/designercore/instances/interactiveconnectionmanager.cpp b/src/plugins/qmldesigner/designercore/instances/interactiveconnectionmanager.cpp
index dd2f47e555..1c02b5a063 100644
--- a/src/plugins/qmldesigner/designercore/instances/interactiveconnectionmanager.cpp
+++ b/src/plugins/qmldesigner/designercore/instances/interactiveconnectionmanager.cpp
@@ -50,15 +50,14 @@ void InteractiveConnectionManager::setUp(NodeInstanceServerInterface *nodeInstan
 {
     ConnectionManager::setUp(nodeInstanceServer, qrcMappingString, target, view);
 
-    DesignerSettings settings = QmlDesignerPlugin::instance()->settings();
-    int timeOutTime = settings.value(DesignerSettingsKey::PUPPET_KILL_TIMEOUT).toInt();
+    int timeOutTime = QmlDesignerPlugin::settings()
+            .value(DesignerSettingsKey::PUPPET_KILL_TIMEOUT).toInt();
     for (Connection &connection : connections()) {
         connection.timer.reset(new QTimer);
         connection.timer->setInterval(timeOutTime);
     }
 
-    if (QmlDesignerPlugin::instance()
-            ->settings()
+    if (QmlDesignerPlugin::settings()
             .value(DesignerSettingsKey::DEBUG_PUPPET)
             .toString()
             .isEmpty()) {
diff --git a/src/plugins/qmldesigner/designercore/instances/puppetcreator.cpp b/src/plugins/qmldesigner/designercore/instances/puppetcreator.cpp
index f2baf9c984..262811747c 100644
--- a/src/plugins/qmldesigner/designercore/instances/puppetcreator.cpp
+++ b/src/plugins/qmldesigner/designercore/instances/puppetcreator.cpp
@@ -149,7 +149,7 @@ bool PuppetCreator::useOnlyFallbackPuppet() const
 #ifndef QMLDESIGNER_TEST
     if (!m_target || !m_target->kit()->isValid())
         qWarning() << "Invalid kit for QML puppet";
-    return m_designerSettings.value(DesignerSettingsKey::USE_DEFAULT_PUPPET).toBool()
+    return QmlDesignerPlugin::settings().value(DesignerSettingsKey::USE_DEFAULT_PUPPET).toBool()
             || m_target == nullptr || !m_target->kit()->isValid();
 #else
     return true;
@@ -188,9 +188,6 @@ PuppetCreator::PuppetCreator(ProjectExplorer::Target *target, const Model *model
     : m_target(target)
     , m_availablePuppetType(FallbackPuppet)
     , m_model(model)
-#ifndef QMLDESIGNER_TEST
-    , m_designerSettings(QmlDesignerPlugin::instance()->settings())
-#endif
 {
 }
 
@@ -232,7 +229,7 @@ QProcessUniquePointer PuppetCreator::puppetProcess(
                      processFinishCallback);
 
 #ifndef QMLDESIGNER_TEST
-    QString forwardOutput = m_designerSettings.value(DesignerSettingsKey::
+    QString forwardOutput = QmlDesignerPlugin::settings().value(DesignerSettingsKey::
         FORWARD_PUPPET_OUTPUT).toString();
 #else
     QString forwardOutput("all");
@@ -265,7 +262,7 @@ QProcessUniquePointer PuppetCreator::puppetProcess(
     }
 
 #ifndef QMLDESIGNER_TEST
-    QString debugPuppet = m_designerSettings.value(DesignerSettingsKey::
+    QString debugPuppet = QmlDesignerPlugin::settings().value(DesignerSettingsKey::
         DEBUG_PUPPET).toString();
 #else
     QString debugPuppet("all");
@@ -415,7 +412,7 @@ QString PuppetCreator::defaultPuppetToplevelBuildDirectory()
 QString PuppetCreator::qmlPuppetToplevelBuildDirectory() const
 {
 #ifndef QMLDESIGNER_TEST
-    QString puppetToplevelBuildDirectory = m_designerSettings.value(
+    QString puppetToplevelBuildDirectory = QmlDesignerPlugin::settings().value(
                 DesignerSettingsKey::PUPPET_TOPLEVEL_BUILD_DIRECTORY).toString();
     if (puppetToplevelBuildDirectory.isEmpty())
         return defaultPuppetToplevelBuildDirectory();
@@ -435,7 +432,7 @@ QString PuppetCreator::qmlPuppetDirectory(PuppetType puppetType) const
     if (puppetType == BinPathPuppet)
         return pathForBinPuppet(m_target).toFileInfo().absoluteDir().canonicalPath();
 
-    return qmlPuppetFallbackDirectory(m_designerSettings);
+    return qmlPuppetFallbackDirectory(QmlDesignerPlugin::settings());
 #else
     return QString();
 #endif
@@ -503,10 +500,10 @@ QProcessEnvironment PuppetCreator::processEnvironment() const
         environment.set("QT_AUTO_SCREEN_SCALE_FACTOR", "1");
 
 #ifndef QMLDESIGNER_TEST
-    const QString controlsStyle = m_designerSettings.value(DesignerSettingsKey::
+    const QString controlsStyle = QmlDesignerPlugin::settings().value(DesignerSettingsKey::
             CONTROLS_STYLE).toString();
 
-    const bool smoothRendering = m_designerSettings.value(DesignerSettingsKey::SMOOTH_RENDERING)
+    const bool smoothRendering = QmlDesignerPlugin::settings().value(DesignerSettingsKey::SMOOTH_RENDERING)
                                      .toBool();
 
     if (smoothRendering)
@@ -553,7 +550,7 @@ QProcessEnvironment PuppetCreator::processEnvironment() const
             environment.set("QMLDESIGNER_FORCE_QAPPLICATION", "true");
     }
 
-    bool particlemode = QmlDesigner::DesignerSettings::getValue("particleMode").toBool();
+    bool particlemode = QmlDesigner::QmlDesignerPlugin::settings().value("particleMode").toBool();
     if (!particlemode)
         environment.set("QT_QUICK3D_DISABLE_PARTICLE_SYSTEMS", "1");
     else
diff --git a/src/plugins/qmldesigner/designercore/instances/puppetcreator.h b/src/plugins/qmldesigner/designercore/instances/puppetcreator.h
index 341e44c4df..2516c2d27e 100644
--- a/src/plugins/qmldesigner/designercore/instances/puppetcreator.h
+++ b/src/plugins/qmldesigner/designercore/instances/puppetcreator.h
@@ -108,9 +108,6 @@ private:
     PuppetType m_availablePuppetType;
     static QHash<Utils::Id, PuppetType> m_qml2PuppetForKitPuppetHash;
     const Model *m_model = nullptr;
-#ifndef QMLDESIGNER_TEST
-    const DesignerSettings m_designerSettings;
-#endif
     QString m_qrcMapping;
 };
 
diff --git a/src/plugins/qmldesigner/designercore/model/qmlobjectnode.cpp b/src/plugins/qmldesigner/designercore/model/qmlobjectnode.cpp
index 64a562c029..e5ea12a058 100644
--- a/src/plugins/qmldesigner/designercore/model/qmlobjectnode.cpp
+++ b/src/plugins/qmldesigner/designercore/model/qmlobjectnode.cpp
@@ -677,10 +677,10 @@ QString QmlObjectNode::generateTranslatableText(const QString &text)
 {
 #ifndef QMLDESIGNER_TEST
 
-    if (QmlDesignerPlugin::instance()->settings().value(
+    if (QmlDesignerPlugin::settings().value(
             DesignerSettingsKey::TYPE_OF_QSTR_FUNCTION).toInt())
 
-        switch (QmlDesignerPlugin::instance()->settings().value(
+        switch (QmlDesignerPlugin::settings().value(
                     DesignerSettingsKey::TYPE_OF_QSTR_FUNCTION).toInt()) {
         case 0: return QString(QStringLiteral("qsTr(\"%1\")")).arg(text);
         case 1: return QString(QStringLiteral("qsTrId(\"%1\")")).arg(text);
diff --git a/src/plugins/qmldesigner/designersettings.cpp b/src/plugins/qmldesigner/designersettings.cpp
index 8841267385..dacadf7404 100644
--- a/src/plugins/qmldesigner/designersettings.cpp
+++ b/src/plugins/qmldesigner/designersettings.cpp
@@ -25,8 +25,6 @@
 
 #include "designersettings.h"
 
-#include <qmldesignerplugin.h>
-
 #include <QSettings>
 
 namespace QmlDesigner {
@@ -36,11 +34,35 @@ namespace DesignerSettingsGroupKey {
     const char QML_DESIGNER_SETTINGS_GROUP[] = "Designer";
 }
 
-DesignerSettings::DesignerSettings() = default;
+DesignerSettings::DesignerSettings(QSettings *settings) :
+    m_settings(settings)
+{
+    fromSettings(settings);
+}
+
+void DesignerSettings::insert(const QByteArray &key, const QVariant &value)
+{
+    QMutexLocker locker(&m_mutex);
+    m_cache.insert(key, value);
+    toSettings(m_settings);
+}
+
+void DesignerSettings::insert(const QHash<QByteArray, QVariant> &settingsHash)
+{
+    QMutexLocker locker(&m_mutex);
+    m_cache.insert(settingsHash);
+    toSettings(m_settings);
+}
+
+QVariant DesignerSettings::value(const QByteArray &key, const QVariant &defaultValue) const
+{
+    QMutexLocker locker(&m_mutex);
+    return m_cache.value(key);
+}
 
 void DesignerSettings::restoreValue(QSettings *settings, const QByteArray &key, const QVariant &defaultValue)
 {
-    insert(key, settings->value(QString::fromLatin1(key), defaultValue));
+    m_cache.insert(key, settings->value(QString::fromLatin1(key), defaultValue));
 }
 
 void DesignerSettings::fromSettings(QSettings *settings)
@@ -80,8 +102,8 @@ void DesignerSettings::fromSettings(QSettings *settings)
     restoreValue(settings, DesignerSettingsKey::ALWAYS_DESIGN_MODE, true);
     restoreValue(settings, DesignerSettingsKey::DISABLE_ITEM_LIBRARY_UPDATE_TIMER, false);
     restoreValue(settings, DesignerSettingsKey::ASK_BEFORE_DELETING_ASSET, true);
-    const QStringList defaultValue = QStringList() << "#222222" << "#999999";
-    restoreValue(settings, DesignerSettingsKey::EDIT3DVIEW_BACKGROUND_COLOR, defaultValue);
+    restoreValue(settings, DesignerSettingsKey::EDIT3DVIEW_BACKGROUND_COLOR,
+                 QStringList{"#222222", "#999999"});
     restoreValue(settings, DesignerSettingsKey::EDIT3DVIEW_GRID_COLOR, "#aaaaaa");
     restoreValue(settings, DesignerSettingsKey::SMOOTH_RENDERING, false);
     restoreValue(settings, DesignerSettingsKey::SHOW_DEBUG_SETTINGS, false);
@@ -103,8 +125,8 @@ void DesignerSettings::toSettings(QSettings *settings) const
     settings->beginGroup(QLatin1String(DesignerSettingsGroupKey::QML_SETTINGS_GROUP));
     settings->beginGroup(QLatin1String(DesignerSettingsGroupKey::QML_DESIGNER_SETTINGS_GROUP));
 
-    QHash<QByteArray, QVariant>::const_iterator i = constBegin();
-    while (i != constEnd()) {
+    QHash<QByteArray, QVariant>::const_iterator i = m_cache.constBegin();
+    while (i != m_cache.constEnd()) {
         storeValue(settings, i.key(), i.value());
         ++i;
     }
@@ -113,17 +135,4 @@ void DesignerSettings::toSettings(QSettings *settings) const
     settings->endGroup();
 }
 
-QVariant DesignerSettings::getValue(const QByteArray &key)
-{
-    DesignerSettings settings = QmlDesignerPlugin::instance()->settings();
-    return settings.value(key);
-}
-
-void DesignerSettings::setValue(const QByteArray &key, const QVariant &value)
-{
-    DesignerSettings settings = QmlDesignerPlugin::instance()->settings();
-    settings.insert(key, value);
-    QmlDesignerPlugin::instance()->setSettings(settings);
-}
-
 } // namespace QmlDesigner
diff --git a/src/plugins/qmldesigner/designersettings.h b/src/plugins/qmldesigner/designersettings.h
index 851a5e8ef2..c3d014cc34 100644
--- a/src/plugins/qmldesigner/designersettings.h
+++ b/src/plugins/qmldesigner/designersettings.h
@@ -30,6 +30,7 @@
 #include <QHash>
 #include <QVariant>
 #include <QByteArray>
+#include <QMutex>
 
 QT_BEGIN_NAMESPACE
 class QSettings;
@@ -77,19 +78,25 @@ const char SMOOTH_RENDERING[] = "SmoothRendering";
 const char OLD_STATES_EDITOR[] = "OldStatesEditor";
 }
 
-class QMLDESIGNERCORE_EXPORT DesignerSettings : public QHash<QByteArray, QVariant>
+class QMLDESIGNERCORE_EXPORT DesignerSettings
 {
 public:
-    DesignerSettings();
+    DesignerSettings(QSettings *settings);
 
+    void insert(const QByteArray &key, const QVariant &value);
+    void insert(const QHash<QByteArray, QVariant> &settingsHash);
+    QVariant value(const QByteArray &key, const QVariant &defaultValue = {}) const;
+
+private:
     void fromSettings(QSettings *);
     void toSettings(QSettings *) const;
-    static QVariant getValue(const QByteArray &key);
-    static void setValue(const QByteArray &key, const QVariant &value);
-private:
     void restoreValue(QSettings *settings, const QByteArray &key,
         const QVariant &defaultValue = QVariant());
     void storeValue(QSettings *settings, const QByteArray &key, const QVariant &value) const;
+
+    QSettings *m_settings;
+    QHash<QByteArray, QVariant> m_cache;
+    mutable QMutex m_mutex;
 };
 
 } // namespace QmlDesigner
diff --git a/src/plugins/qmldesigner/documentwarningwidget.cpp b/src/plugins/qmldesigner/documentwarningwidget.cpp
index e691912fb9..cfa512e30d 100644
--- a/src/plugins/qmldesigner/documentwarningwidget.cpp
+++ b/src/plugins/qmldesigner/documentwarningwidget.cpp
@@ -200,12 +200,12 @@ void DocumentWarningWidget::emitGotoCodeClicked(const DocumentMessage &message)
 
 bool DocumentWarningWidget::warningsEnabled() const
 {
-    return DesignerSettings::getValue(DesignerSettingsKey::WARNING_FOR_FEATURES_IN_DESIGNER).toBool();
+    return QmlDesignerPlugin::settings().value(DesignerSettingsKey::WARNING_FOR_FEATURES_IN_DESIGNER).toBool();
 }
 
 void DocumentWarningWidget::ignoreCheckBoxToggled(bool b)
 {
-    DesignerSettings::setValue(DesignerSettingsKey::WARNING_FOR_FEATURES_IN_DESIGNER, !b);
+    QmlDesignerPlugin::settings().value(DesignerSettingsKey::WARNING_FOR_FEATURES_IN_DESIGNER, !b);
 }
 
 void DocumentWarningWidget::setErrors(const QList<DocumentMessage> &errors)
diff --git a/src/plugins/qmldesigner/openuiqmlfiledialog.cpp b/src/plugins/qmldesigner/openuiqmlfiledialog.cpp
index 8bd5a0e17c..8fa4648a74 100644
--- a/src/plugins/qmldesigner/openuiqmlfiledialog.cpp
+++ b/src/plugins/qmldesigner/openuiqmlfiledialog.cpp
@@ -55,9 +55,8 @@ OpenUiQmlFileDialog::OpenUiQmlFileDialog(QWidget *parent) :
         close();
     });
     connect(ui->checkBox, &QCheckBox::toggled, this, [](bool b){
-        DesignerSettings settings = QmlDesignerPlugin::instance()->settings();
-        settings.insert(DesignerSettingsKey::WARNING_FOR_QML_FILES_INSTEAD_OF_UIQML_FILES, !b);
-        QmlDesignerPlugin::instance()->setSettings(settings);
+        QmlDesignerPlugin::settings().insert(
+            DesignerSettingsKey::WARNING_FOR_QML_FILES_INSTEAD_OF_UIQML_FILES, !b);
     });
 }
 
diff --git a/src/plugins/qmldesigner/qmldesignerplugin.cpp b/src/plugins/qmldesigner/qmldesignerplugin.cpp
index 4890205f42..6226e54e80 100644
--- a/src/plugins/qmldesigner/qmldesignerplugin.cpp
+++ b/src/plugins/qmldesigner/qmldesignerplugin.cpp
@@ -124,7 +124,7 @@ QtQuickDesignerFactory::QtQuickDesignerFactory()
     setDocumentCreator([this]() {
         auto document = new QmlJSEditor::QmlJSEditorDocument(id());
         document->setIsDesignModePreferred(
-                    QmlDesigner::DesignerSettings::getValue(
+                    QmlDesigner::QmlDesignerPlugin::settings().value(
                         QmlDesigner::DesignerSettingsKey::ALWAYS_DESIGN_MODE).toBool());
         return document;
     });
@@ -135,6 +135,7 @@ QtQuickDesignerFactory::QtQuickDesignerFactory()
 class QmlDesignerPluginPrivate
 {
 public:
+    DesignerSettings settings{Core::ICore::instance()->settings()};
     QmlDesignerProjectManager projectManager;
     ViewManager viewManager{projectManager.asynchronousImageCache(),
                             projectManager.asynchronousMeshImageCache()};
@@ -142,7 +143,6 @@ public:
     ShortCutManager shortCutManager;
     SettingsPage settingsPage;
     DesignModeWidget mainWidget;
-    DesignerSettings settings;
     QtQuickDesignerFactory m_qtQuickDesignerFactory;
     bool blockEditorChange = false;
 };
@@ -196,7 +196,7 @@ static bool shouldAssertInException()
 
 static bool warningsForQmlFilesInsteadOfUiQmlEnabled()
 {
-    return DesignerSettings::getValue(DesignerSettingsKey::WARNING_FOR_QML_FILES_INSTEAD_OF_UIQML_FILES).toBool();
+    return QmlDesignerPlugin::settings().value(DesignerSettingsKey::WARNING_FOR_QML_FILES_INSTEAD_OF_UIQML_FILES).toBool();
 }
 
 QmlDesignerPlugin::QmlDesignerPlugin()
@@ -297,8 +297,6 @@ bool QmlDesignerPlugin::delayedInitialize()
         });
     MetaInfo::setPluginPaths(pluginPaths);
 
-    d->settings.fromSettings(Core::ICore::settings());
-
     d->viewManager.registerView(std::make_unique<QmlDesigner::Internal::ConnectionView>());
 
     auto timelineView = d->viewManager.registerView(std::make_unique<QmlDesigner::TimelineView>());
@@ -645,7 +643,7 @@ void QmlDesignerPlugin::emitCurrentTextEditorChanged(Core::IEditor *editor)
 
 double QmlDesignerPlugin::formEditorDevicePixelRatio()
 {
-    if (DesignerSettings::getValue(DesignerSettingsKey::IGNORE_DEVICE_PIXEL_RATIO).toBool())
+    if (QmlDesignerPlugin::settings().value(DesignerSettingsKey::IGNORE_DEVICE_PIXEL_RATIO).toBool())
         return 1;
 
     const QList<QWindow *> topLevelWindows = QApplication::topLevelWindows();
@@ -753,18 +751,9 @@ const DesignerActionManager &QmlDesignerPlugin::designerActionManager() const
     return d->viewManager.designerActionManager();
 }
 
-DesignerSettings QmlDesignerPlugin::settings()
+DesignerSettings& QmlDesignerPlugin::settings()
 {
-    d->settings.fromSettings(Core::ICore::settings());
-    return d->settings;
-}
-
-void QmlDesignerPlugin::setSettings(const DesignerSettings &s)
-{
-    if (s != d->settings) {
-        d->settings = s;
-        d->settings.toSettings(Core::ICore::settings());
-    }
+    return instance()->d->settings;
 }
 
 } // namespace QmlDesigner
diff --git a/src/plugins/qmldesigner/qmldesignerplugin.h b/src/plugins/qmldesigner/qmldesignerplugin.h
index 7670d4f1ea..976b9d57c0 100644
--- a/src/plugins/qmldesigner/qmldesignerplugin.h
+++ b/src/plugins/qmldesigner/qmldesignerplugin.h
@@ -75,8 +75,7 @@ public:
     DesignerActionManager &designerActionManager();
     const DesignerActionManager &designerActionManager() const;
 
-    DesignerSettings settings();
-    void setSettings(const DesignerSettings &s);
+    static DesignerSettings& settings();
 
     DesignDocument *currentDesignDocument() const;
     Internal::DesignModeWidget *mainWidget() const;
diff --git a/src/plugins/qmldesigner/settingspage.cpp b/src/plugins/qmldesigner/settingspage.cpp
index 700402680a..7c1530fedb 100644
--- a/src/plugins/qmldesigner/settingspage.cpp
+++ b/src/plugins/qmldesigner/settingspage.cpp
@@ -63,7 +63,7 @@ public:
 
     void apply() final;
 
-    DesignerSettings settings() const;
+    QHash<QByteArray, QVariant> newSettings() const;
     void setSettings(const DesignerSettings &settings);
 
 private:
@@ -108,9 +108,9 @@ SettingsPageWidget::SettingsPageWidget()
     setSettings(QmlDesignerPlugin::instance()->settings());
 }
 
-DesignerSettings SettingsPageWidget::settings() const
+QHash<QByteArray, QVariant> SettingsPageWidget::newSettings() const
 {
-    DesignerSettings settings = QmlDesignerPlugin::instance()->settings();
+    QHash<QByteArray, QVariant> settings;
     settings.insert(DesignerSettingsKey::ITEMSPACING, m_ui.spinItemSpacing->value());
     settings.insert(DesignerSettingsKey::CONTAINERPADDING, m_ui.spinSnapMargin->value());
     settings.insert(DesignerSettingsKey::CANVASWIDTH, m_ui.spinCanvasWidth->value());
@@ -154,7 +154,8 @@ DesignerSettings SettingsPageWidget::settings() const
               m_ui.fallbackPuppetPathLineEdit->lineEdit()->placeholderText());
     if (newFallbackPuppetPath.isEmpty())
         newFallbackPuppetPath = m_ui.fallbackPuppetPathLineEdit->lineEdit()->placeholderText();
-    QString oldFallbackPuppetPath = PuppetCreator::qmlPuppetFallbackDirectory(settings);
+
+    QString oldFallbackPuppetPath = PuppetCreator::qmlPuppetFallbackDirectory(QmlDesignerPlugin::settings());
 
     if (oldFallbackPuppetPath != newFallbackPuppetPath && QFileInfo::exists(newFallbackPuppetPath)) {
         if (newFallbackPuppetPath == PuppetCreator::defaultPuppetFallbackDirectory())
@@ -270,8 +271,7 @@ void SettingsPageWidget::setSettings(const DesignerSettings &settings)
 
 void SettingsPageWidget::apply()
 {
-    DesignerSettings currentSettings(QmlDesignerPlugin::instance()->settings());
-    DesignerSettings newSettings = settings();
+    auto settings = newSettings();
 
     const auto restartNecessaryKeys = {
       DesignerSettingsKey::PUPPET_DEFAULT_DIRECTORY,
@@ -285,7 +285,7 @@ void SettingsPageWidget::apply()
     };
 
     for (const char * const key : restartNecessaryKeys) {
-        if (currentSettings.value(key) != newSettings.value(key)) {
+        if (QmlDesignerPlugin::settings().value(key) != settings.value(key)) {
             QMessageBox::information(Core::ICore::dialogParent(), tr("Restart Required"),
                 tr("The made changes will take effect after a "
                    "restart of the QML Emulation layer or %1.")
@@ -294,7 +294,7 @@ void SettingsPageWidget::apply()
         }
     }
 
-    QmlDesignerPlugin::instance()->setSettings(newSettings);
+    QmlDesignerPlugin::settings().insert(settings);
 }
 
 SettingsPage::SettingsPage()