diff --git a/README b/README
index ae411270f5e..ebc8a6c03ca 100644
--- a/README
+++ b/README
@@ -12,7 +12,9 @@ Mac OS X 10.7 or later
 
 Building the sources requires Qt 5.2.0 or later.
 It is also possible to build with Qt 4.8.x, but in that case the Welcome mode,
-Qt Quick Designer, QML Profiler, and the WinRT and Qbs support are disabled.
+QML Profiler, and the WinRT and Qbs support are disabled.
+The Qt Quick Designer can only be compiled with Qt 5.3.1 or later , because
+it requires QQuickWidget.
 
 Compiling Qt Creator
 ====================
diff --git a/src/plugins/help/helpwidget.cpp b/src/plugins/help/helpwidget.cpp
index e4ba016de2c..aac98239fbc 100644
--- a/src/plugins/help/helpwidget.cpp
+++ b/src/plugins/help/helpwidget.cpp
@@ -61,12 +61,13 @@ HelpWidget::HelpWidget(const Core::Context &context, WidgetStyle style, QWidget
     QWidget(parent),
     m_scaleUp(0),
     m_scaleDown(0),
-    m_resetScale(0)
+    m_resetScale(0),
+    m_style(style)
 {
     Utils::StyledBar *toolBar = new Utils::StyledBar();
 
     QAction *switchToHelp = new QAction(tr("Go to Help Mode"), toolBar);
-    connect(switchToHelp, SIGNAL(triggered()), this, SLOT(emitOpenHelpMode()));
+    connect(switchToHelp, SIGNAL(triggered()), this, SLOT(helpModeButtonClicked()));
 
     QAction *back = new QAction(QIcon(QLatin1String(":/help/images/previous.png")),
         tr("Back"), toolBar);
@@ -123,7 +124,7 @@ HelpWidget::HelpWidget(const Core::Context &context, WidgetStyle style, QWidget
     cmd = Core::ActionManager::registerAction(m_openHelpMode,
                                               Help::Constants::CONTEXT_HELP,
                                               context);
-    connect(m_openHelpMode, SIGNAL(triggered()), this, SLOT(emitOpenHelpMode()));
+    connect(m_openHelpMode, SIGNAL(triggered()), this, SLOT(helpModeButtonClicked()));
 
     Core::ActionContainer *advancedMenu = Core::ActionManager::actionContainer(Core::Constants::M_EDIT_ADVANCED);
     QTC_CHECK(advancedMenu);
@@ -206,9 +207,11 @@ void HelpWidget::updateWindowTitle()
         setWindowTitle(tr("Help - %1").arg(pageTitle));
 }
 
-void HelpWidget::emitOpenHelpMode()
+void HelpWidget::helpModeButtonClicked()
 {
     emit openHelpMode(m_viewer->source());
+    if (m_style == ExternalWindow)
+        close();
 }
 
 } // Internal
diff --git a/src/plugins/help/helpwidget.h b/src/plugins/help/helpwidget.h
index c366c94cd3c..f89bd01eef7 100644
--- a/src/plugins/help/helpwidget.h
+++ b/src/plugins/help/helpwidget.h
@@ -71,7 +71,7 @@ private slots:
     void updateBackMenu();
     void updateForwardMenu();
     void updateWindowTitle();
-    void emitOpenHelpMode();
+    void helpModeButtonClicked();
 
 private:
     QMenu *m_backMenu;
@@ -83,6 +83,7 @@ private:
     QAction *m_copy;
 
     HelpViewer *m_viewer;
+    WidgetStyle m_style;
 };
 
 } // Internal
diff --git a/src/plugins/plugins.pro b/src/plugins/plugins.pro
index 61a62462277..a8d0d6c8807 100644
--- a/src/plugins/plugins.pro
+++ b/src/plugins/plugins.pro
@@ -76,13 +76,18 @@ isEmpty(IDE_PACKAGE_MODE) {
         updateinfo
 }
 
+minQtVersion(5, 3, 1) {
+    SUBDIRS += qmldesigner
+} else {
+     warning("QmlDesigner plugin has been disabled.")
+     warning("This plugin requires Qt 5.3.1 or newer.")
+}
+
 minQtVersion(5, 2, 0) {
     SUBDIRS += \
-        qmldesigner \
         qmlprofiler \
         welcome
 } else {
-     warning("QmlDesigner plugin has been disabled.")
      warning("QmlProfiler plugin has been disabled.")
      warning("Welcome plugin has been disabled.")
      warning("These plugins need at least Qt 5.2.")
diff --git a/src/plugins/projectexplorer/projectexplorer.cpp b/src/plugins/projectexplorer/projectexplorer.cpp
index 13824d827e6..e372b62bd91 100644
--- a/src/plugins/projectexplorer/projectexplorer.cpp
+++ b/src/plugins/projectexplorer/projectexplorer.cpp
@@ -1049,7 +1049,7 @@ bool ProjectExplorerPlugin::initialize(const QStringList &arguments, QString *er
 
     VariableManager::registerFileVariables(Constants::VAR_CURRENTPROJECT_PREFIX,
         tr("Current project's main file"),
-        [&]() -> QString {
+        [this]() -> QString {
             QString projectFilePath;
             if (Project *project = ProjectExplorerPlugin::currentProject())
                 if (IDocument *doc = project->document())
diff --git a/src/plugins/qmakeprojectmanager/qmakeprojectimporter.cpp b/src/plugins/qmakeprojectmanager/qmakeprojectimporter.cpp
index ab1cd48d33c..a51dbb03387 100644
--- a/src/plugins/qmakeprojectmanager/qmakeprojectimporter.cpp
+++ b/src/plugins/qmakeprojectmanager/qmakeprojectimporter.cpp
@@ -245,6 +245,9 @@ ProjectExplorer::Kit *QmakeProjectImporter::createTemporaryKit(QtSupport::BaseQt
                                                                const Utils::FileName &parsedSpec)
 {
     ProjectExplorer::Kit *k = new ProjectExplorer::Kit;
+
+    ProjectExplorer::KitGuard guard(k);
+
     QtSupport::QtKitInformation::setQtVersion(k, version);
     ProjectExplorer::ToolChainKitInformation::setToolChain(k, version->preferredToolChain(parsedSpec));
     QmakeKitInformation::setMkspec(k, parsedSpec);
@@ -253,7 +256,16 @@ ProjectExplorer::Kit *QmakeProjectImporter::createTemporaryKit(QtSupport::BaseQt
     if (temporaryVersion)
         k->setValue(QT_IS_TEMPORARY, version->uniqueId());
 
+    // Set up other values:
+    foreach (ProjectExplorer::KitInformation *ki, ProjectExplorer::KitManager::kitInformation()) {
+        if (ki->id() == ProjectExplorer::ToolChainKitInformation::id()
+                || ki->id() == QtSupport::QtKitInformation::id())
+            continue;
+        ki->setup(k);
+    }
+
     k->setDisplayName(version->displayName());
+
     setIsUpdating(true);
     ProjectExplorer::KitManager::registerKit(k);
     setIsUpdating(false);
diff --git a/src/plugins/welcome/welcomeplugin.cpp b/src/plugins/welcome/welcomeplugin.cpp
index 57779ff4a2c..f5b0b2d1467 100644
--- a/src/plugins/welcome/welcomeplugin.cpp
+++ b/src/plugins/welcome/welcomeplugin.cpp
@@ -68,11 +68,6 @@ static const char currentPageSettingsKeyC[] = "WelcomeTab";
 namespace Welcome {
 namespace Internal {
 
-struct WelcomeModePrivate
-{
-
-};
-
 class WelcomeMode : public Core::IMode
 {
     Q_OBJECT