QmlDesigner: Focus the content widget of the dock when focusing tab

When DockWidgetTab or DockWidget is focused, typically user actually
wants to focus the content widget, so we now do that.
Focusing content widget is done asynchronously to avoid complications
from doing another setFocus in middle of setFocus handling.

(cherry picked from commit ce3d4b6a59b620d066f0e764634de54131921f8b)
Fixes: QDS-9104
Change-Id: I569639c2f36f0721aafcdcab3498c875e98993a9
Reviewed-by: Thomas Hartmann <thomas.hartmann@qt.io>
Reviewed-by: Miikka Heikkinen <miikka.heikkinen@qt.io>
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>

share/qtcreator/qmldesigner/materialBrowserQmlSource/MaterialBrowser.qml

@@ -9,6 +9,7 @@ import StudioTheme 1.0 as StudioTheme
 
 Item {
     id: root
+    focus: true
 
     readonly property int cellWidth: 100
     readonly property int cellHeight: 120

src/libs/advanceddockingsystem/dockfocuscontroller.cpp

@@ -162,6 +162,8 @@ namespace ADS
         if (!dockWidget)
             dockWidget = qobject_cast<DockWidget *>(focusedNow);
 
+        bool focusActual = dockWidget && dockWidget->widget();
+
         if (!dockWidget)
             dockWidget = internal::findParent<DockWidget *>(focusedNow);
 
@@ -174,6 +176,12 @@ namespace ADS
     #endif
 
         d->updateDockWidgetFocus(dockWidget);
+
+        if (focusActual) {
+            // Do this async to avoid issues when changing focus in middle of another focus handling
+            QMetaObject::invokeMethod(dockWidget->widget(), QOverload<>::of(&QWidget::setFocus),
+                                      Qt::QueuedConnection);
+        }
     }
 
     void DockFocusController::setDockWidgetFocused(DockWidget *focusedNow)

src/plugins/qmldesigner/components/materialbrowser/materialbrowserwidget.cpp

@@ -207,6 +207,8 @@ MaterialBrowserWidget::MaterialBrowserWidget(AsynchronousImageCache &imageCache,
     QmlDesignerPlugin::trackWidgetFocusTime(this, Constants::EVENT_MATERIALBROWSER_TIME);
 
     reloadQmlSource();
+
+    setFocusProxy(m_quickWidget.data());
 }
 
 void MaterialBrowserWidget::updateMaterialPreview(const ModelNode &node, const QPixmap &pixmap)

src/plugins/qmldesigner/components/navigator/navigatorwidget.cpp

@@ -66,6 +66,8 @@ NavigatorWidget::NavigatorWidget(NavigatorView *view)
     setStyleSheet(Theme::replaceCssColors(QString::fromUtf8(sheet)));
 
     QmlDesignerPlugin::trackWidgetFocusTime(this, Constants::EVENT_NAVIGATORVIEW_TIME);
+
+    setFocusProxy(m_treeView);
 }
 
 void NavigatorWidget::setTreeModel(QAbstractItemModel *model)