updateTitleBarVisibility after deserializing

Fixes floating window having two title bars

src/private/FloatingWindow.cpp

@@ -336,6 +336,9 @@ void FloatingWindow::updateTitleBarVisibility()
                 visible = !frames().first()->hasTabsVisible();
             }
         }
+
+        for (Frame *frame : frames())
+            frame->updateTitleBarVisibility();
     }
 
     m_titleBar->setVisible(visible);
@@ -390,6 +393,7 @@ void FloatingWindow::onCloseEvent(QCloseEvent *e)
 bool FloatingWindow::deserialize(const LayoutSaver::FloatingWindow &fw)
 {
     if (dropArea()->multiSplitterLayout()->deserialize(fw.multiSplitterLayout)) {
+        updateTitleBarVisibility();
         show();
         return true;
     } else {

src/private/Frame.cpp

@@ -201,6 +201,13 @@ void Frame::onCurrentTabChanged(int index)
 
 void Frame::updateTitleBarVisibility()
 {
+    if (m_updatingTitleBar) {
+        // To break a cyclic dependency
+        return;
+    }
+
+    QScopedValueRollback<bool> guard(m_updatingTitleBar, true);
+
     bool visible = false;
     if (isCentralFrame()) {
         visible = false;
@@ -214,8 +221,11 @@ void Frame::updateTitleBarVisibility()
     }
 
     m_titleBar->setVisible(visible);
-    if (auto fw = floatingWindow())
+    if (auto fw = floatingWindow()) {
+        // Update the floating window which might be using Flag_HideTitleBarWhenTabsVisible
+        // In that case it might not show title bar depending on the number of tabs that the frame has
         fw->updateTitleBarVisibility();
+    }
 }
 
 bool Frame::containsMouse(QPoint globalPos) const

src/private/Frame_p.h

@@ -223,6 +223,7 @@ private:
     DropArea *m_dropArea = nullptr;
     const FrameOptions m_options;
     QPointer<Layouting::Item> m_layoutItem;
+    bool m_updatingTitleBar = false;
     bool m_beingDeleted = false;
     QMetaObject::Connection m_visibleWidgetCountChangedConnection;
 };

tests/tst_docks.cpp

@@ -5301,6 +5301,32 @@ void TestDocks::tst_moreTitleBarCornerCases()
         delete fw1;
         delete fw2;
     }
+
+    {
+        // Tests that restoring a single floating dock widget doesn't make it show two title-bars
+        // As reproduced myself... and fixed in this commit
+
+        EnsureTopLevelsDeleted e;
+        auto dock1 = createDockWidget("dock1", new QPushButton("foo1"));
+        dock1->show();
+
+        auto fw1 = qobject_cast<FloatingWindow*>(dock1->window());
+        QVERIFY(!dock1->frame()->titleBar()->isVisible());
+        QVERIFY(fw1->titleBar()->isVisible());
+
+        LayoutSaver saver;
+        const QByteArray saved = saver.serializeLayout();
+        saver.restoreLayout(saved);
+
+        delete fw1; // the old window
+
+        fw1 = qobject_cast<FloatingWindow*>(dock1->window());
+        QVERIFY(dock1->isVisible());
+        QVERIFY(!dock1->frame()->titleBar()->isVisible());
+        QVERIFY(fw1->titleBar()->isVisible());
+        delete dock1->window();
+    }
+
 }
 
 int main(int argc, char *argv[])