6 files changed, 17 insertions, 0 deletions

diff --git a/src/widgets/accessible/itemviews.cpp b/src/widgets/accessible/itemviews.cpp
index db5af4fd7c..eec9a0021c 100644
--- a/src/widgets/accessible/itemviews.cpp
+++ b/src/widgets/accessible/itemviews.cpp
@@ -310,6 +310,7 @@ bool QAccessibleTable::selectColumn(int column)
     case QAbstractItemView::SingleSelection:
         if (view()->selectionBehavior() != QAbstractItemView::SelectColumns && rowCount() > 1)
             return false;
+        Q_FALLTHROUGH();
     case QAbstractItemView::ContiguousSelection:
         if ((!column || !view()->selectionModel()->isColumnSelected(column - 1, view()->rootIndex()))
             && !view()->selectionModel()->isColumnSelected(column + 1, view()->rootIndex()))
diff --git a/src/widgets/graphicsview/qgraphicswidget.cpp b/src/widgets/graphicsview/qgraphicswidget.cpp
index 2adc58e4a4..1ff01b875c 100644
--- a/src/widgets/graphicsview/qgraphicswidget.cpp
+++ b/src/widgets/graphicsview/qgraphicswidget.cpp
@@ -1500,6 +1500,7 @@ void QGraphicsWidget::changeEvent(QEvent *event)
         unsetWindowFrameMargins();
         if (d->layout)
             d->layout->invalidate();
+        Q_FALLTHROUGH();
     case QEvent::FontChange:
         update();
         updateGeometry();
diff --git a/src/widgets/itemviews/qabstractitemview.cpp b/src/widgets/itemviews/qabstractitemview.cpp
index 20002b1f82..d24456edef 100644
--- a/src/widgets/itemviews/qabstractitemview.cpp
+++ b/src/widgets/itemviews/qabstractitemview.cpp
@@ -4035,6 +4035,7 @@ QItemSelectionModel::SelectionFlags QAbstractItemViewPrivate::extendedSelectionC
             switch (static_cast<const QKeyEvent*>(event)->key()) {
             case Qt::Key_Backtab:
                 modifiers = modifiers & ~Qt::ShiftModifier; // special case for backtab
+                Q_FALLTHROUGH();
             case Qt::Key_Down:
             case Qt::Key_Up:
             case Qt::Key_Left:
diff --git a/src/widgets/itemviews/qheaderview.cpp b/src/widgets/itemviews/qheaderview.cpp
index d2f9618c29..e0e993ce77 100644
--- a/src/widgets/itemviews/qheaderview.cpp
+++ b/src/widgets/itemviews/qheaderview.cpp
@@ -2565,6 +2565,7 @@ void QHeaderView::mouseReleaseEvent(QMouseEvent *e)
             d->updateSectionIndicator(d->section, pos);
             break;
         } // not moving
+        Q_FALLTHROUGH();
     case QHeaderViewPrivate::SelectSections:
         if (!d->clickableSections) {
             int section = logicalIndexAt(pos);
diff --git a/src/widgets/itemviews/qlistview.cpp b/src/widgets/itemviews/qlistview.cpp
index 653b03ef0d..3ef5b788c6 100644
--- a/src/widgets/itemviews/qlistview.cpp
+++ b/src/widgets/itemviews/qlistview.cpp
@@ -1157,6 +1157,7 @@ QModelIndex QListView::moveCursor(CursorAction cursorAction, Qt::KeyboardModifie
         rect.moveTop(rect.top() - d->viewport->height() + 2 * rect.height());
         if (rect.top() < rect.height())
             rect.moveTop(rect.height());
+        Q_FALLTHROUGH();
     case MovePrevious:
     case MoveUp:
         while (intersectVector.isEmpty()) {
@@ -1185,6 +1186,7 @@ QModelIndex QListView::moveCursor(CursorAction cursorAction, Qt::KeyboardModifie
         rect.moveTop(rect.top() + d->viewport->height() - 2 * rect.height());
         if (rect.bottom() > contents.height() - rect.height())
             rect.moveBottom(contents.height() - rect.height());
+        Q_FALLTHROUGH();
     case MoveNext:
     case MoveDown:
         while (intersectVector.isEmpty()) {
diff --git a/src/widgets/widgets/qmenubar.cpp b/src/widgets/widgets/qmenubar.cpp
index 77ed7a4f78..c16b2a5ac1 100644
--- a/src/widgets/widgets/qmenubar.cpp
+++ b/src/widgets/widgets/qmenubar.cpp
@@ -1470,6 +1470,17 @@ bool QMenuBar::eventFilter(QObject *object, QEvent *event)
         }
     }
 
+    if (isNativeMenuBar() && event->type() == QEvent::ShowToParent) {
+        // On some desktops like Unity, the D-Bus menu bar is unregistered
+        // when the window is hidden. So when the window is shown, we need
+        // to forcefully re-register it. The only way to force re-registering
+        // with D-Bus menu is the handleReparent method.
+        QWidget *widget = qobject_cast<QWidget *>(object);
+        QWindow *handle = widget ? widget->windowHandle() : nullptr;
+        if (handle != nullptr)
+            d->platformMenuBar->handleReparent(handle);
+    }
+
     if (style()->styleHint(QStyle::SH_MenuBar_AltKeyNavigation, 0, this)) {
         if (d->altPressed) {
             switch (event->type()) {