diff --git a/src/gui/kernel/qrasterwindow.cpp b/src/gui/kernel/qrasterwindow.cpp
index 19d84c601d8..7888db67777 100644
--- a/src/gui/kernel/qrasterwindow.cpp
+++ b/src/gui/kernel/qrasterwindow.cpp
@@ -38,10 +38,9 @@ public:
     {
         Q_Q(QRasterWindow);
         const QSize size = q->size();
-        if (backingstore->size() != size) {
+        if (backingstore->size() != size)
             backingstore->resize(size);
-            markWindowAsDirty();
-        }
+
         backingstore->beginPaint(region);
     }
 
@@ -102,6 +101,13 @@ QPaintDevice *QRasterWindow::redirected(QPoint *) const
     return d->backingstore->paintDevice();
 }
 
+void QRasterWindow::resizeEvent(QResizeEvent *)
+{
+    Q_D(QRasterWindow);
+    if (d->backingstore->size() != size())
+        d->markWindowAsDirty();
+}
+
 QT_END_NAMESPACE
 
 #include "moc_qrasterwindow.cpp"
diff --git a/src/gui/kernel/qrasterwindow.h b/src/gui/kernel/qrasterwindow.h
index 05d71e16552..986bf6b511d 100644
--- a/src/gui/kernel/qrasterwindow.h
+++ b/src/gui/kernel/qrasterwindow.h
@@ -23,6 +23,7 @@ public:
 protected:
     int metric(PaintDeviceMetric metric) const override;
     QPaintDevice *redirected(QPoint *) const override;
+    void resizeEvent(QResizeEvent *event) override;
 
 private:
     Q_DISABLE_COPY(QRasterWindow)