diff -r ef0373b55136 -r 758a864f9613 src/gui/painting/qwindowsurface_qws.cpp
--- a/src/gui/painting/qwindowsurface_qws.cpp	Fri Sep 17 08:34:18 2010 +0300
+++ b/src/gui/painting/qwindowsurface_qws.cpp	Mon Oct 04 01:19:32 2010 +0300
@@ -882,7 +882,11 @@
         const QVector<QRect> rects = rgn.rects();
         const QColor blank = Qt::transparent;
         for (QVector<QRect>::const_iterator it = rects.begin(); it != rects.end(); ++it) {
-            p.fillRect(*it, blank);
+            QRect r = *it;
+#ifdef Q_BACKINGSTORE_SUBSURFACES
+            r.translate(painterOffset());
+#endif
+            p.fillRect(r, blank);
         }
     }
     QWSWindowSurface::beginPaint(rgn);