1 files changed, 4 insertions, 2 deletions
diff --git a/src/widgets/widgets/qmdisubwindow.cpp b/src/widgets/widgets/qmdisubwindow.cpp
index 14aeb73baf..be6cb7c54c 100644
--- a/src/widgets/widgets/qmdisubwindow.cpp
+++ b/src/widgets/widgets/qmdisubwindow.cpp
@@ -1000,7 +1000,9 @@ void QMdiSubWindowPrivate::removeBaseWidget()
         q->setWindowModified(false);
     }
     lastChildWindowTitle.clear();
-    baseWidget->setParent(0);
+    // QTBUG-47993: parent widget can be reset before this call
+    if (baseWidget->parentWidget() == q)
+        baseWidget->setParent(0);
     baseWidget = 0;
     isWidgetHiddenByUs = false;
 }
@@ -2653,7 +2655,7 @@ void QMdiSubWindow::showShaded()
     resize(d->internalMinimumSize);
 
     // Hide the internal widget if not already hidden by the user.
-    if (d->baseWidget && !d->baseWidget->isHidden()) {
+    if (d->baseWidget && !d->baseWidget->isHidden() && !(windowFlags() & Qt::FramelessWindowHint)) {
         d->baseWidget->hide();
         d->isWidgetHiddenByUs = true;
     }