--- a/src/plugins/qmltooling/qmldbg_preview/qqmlpreviewhandler.cpp
+++ b/src/plugins/qmltooling/qmldbg_preview/qqmlpreviewhandler.cpp
@@ -115,7 +115,7 @@ bool QQmlPreviewHandler::eventFilter(QObject *obj, QEvent *event)
             qobject_cast<QQuickWindow*>(obj) == m_currentWindow) {
         // we always start with factor 1 so calculate and save the origin as it would be not scaled
         m_lastPosition.setPosition(m_currentWindow->framePosition() *
-                                    QHighDpiScaling::factor(m_currentWindow));
+                                    QHighDpiScaling::factor(m_currentWindow.data()));
     }
 
     return QObject::eventFilter(obj, event);
@@ -214,7 +214,7 @@ void QQmlPreviewHandler::zoom(qreal newFactor)
     // On single-window devices we allow any scale factor as the window will adapt to the screen.
     if (m_supportsMultipleWindows) {
         const QSize newAvailableScreenSize = QQmlPreviewPosition::currentScreenSize(m_currentWindow)
-                * QHighDpiScaling::factor(m_currentWindow) / newFactor;
+                * QHighDpiScaling::factor(m_currentWindow.data()) / newFactor;
         if (m_currentWindow->size().width() > newAvailableScreenSize.width()) {
             errorMessage = QString::fromLatin1(
                         "Zooming with factor: "
@@ -229,7 +229,7 @@ void QQmlPreviewHandler::zoom(qreal newFactor)
 
     if (errorMessage.isEmpty()) {
         const QPoint newToOriginMappedPosition = m_currentWindow->position() *
-                QHighDpiScaling::factor(m_currentWindow) / newFactor;
+                QHighDpiScaling::factor(m_currentWindow.data()) / newFactor;
         m_currentWindow->destroy();
         QHighDpiScaling::setScreenFactor(m_currentWindow->screen(), newFactor);
         if (resetZoom)