2 files changed, 21 insertions, 1 deletions
diff --git a/src/widgets/widgets/qmainwindowlayout.cpp b/src/widgets/widgets/qmainwindowlayout.cpp
index e9cfd05007a..f51fc414941 100644
--- a/src/widgets/widgets/qmainwindowlayout.cpp
+++ b/src/widgets/widgets/qmainwindowlayout.cpp
@@ -432,6 +432,25 @@ void QDockWidgetGroupWindow::destroyOrHideIfEmpty()
     deleteLater();
 }
 
+/*!
+   \internal
+   \return \c true if the group window has at least one visible QDockWidget child,
+   otherwise false.
+ */
+bool QDockWidgetGroupWindow::hasVisibleDockWidgets() const
+{
+    const auto &children = findChildren<QDockWidget *>(Qt::FindChildrenRecursively);
+    for (auto child : children) {
+        // WA_WState_Visible is set on the dock widget, associated to the active tab
+        // and unset on all others.
+        // WA_WState_Hidden is set if the dock widgets have been explicitly hidden.
+        // This is the relevant information to check (equivalent to !child->isHidden()).
+        if (!child->testAttribute(Qt::WA_WState_Hidden))
+            return true;
+    }
+    return false;
+}
+
 /*! \internal
     Sets the flags of this window in accordance to the capabilities of the dock widgets
  */
@@ -480,7 +499,7 @@ void QDockWidgetGroupWindow::adjustFlags()
             m_removedFrameSize = QSize();
         }
 
-        show(); // setWindowFlags hides the window
+        setVisible(hasVisibleDockWidgets());
     }
 
     QWidget *titleBarOf = top ? top : parentWidget();
diff --git a/src/widgets/widgets/qmainwindowlayout_p.h b/src/widgets/widgets/qmainwindowlayout_p.h
index e3d1bb1eeb1..f09c9e82f43 100644
--- a/src/widgets/widgets/qmainwindowlayout_p.h
+++ b/src/widgets/widgets/qmainwindowlayout_p.h
@@ -316,6 +316,7 @@ public:
     QDockWidget *activeTabbedDockWidget() const;
 #endif
     void destroyOrHideIfEmpty();
+    bool hasVisibleDockWidgets() const;
     void adjustFlags();
     bool hasNativeDecos() const;