diff --git a/src/gui/painting/qbackingstore.cpp b/src/gui/painting/qbackingstore.cpp
index 60013fc..5dc9164 100644
--- a/src/gui/painting/qbackingstore.cpp
+++ b/src/gui/painting/qbackingstore.cpp
@@ -941,9 +941,7 @@ void QWidgetPrivate::moveRect(const QRect &rect, int dx, int dy)
 #endif
     const QRect newRect(rect.translated(dx, dy));
     QRect destRect = rect.intersected(clipR);
-    if (destRect.isValid())
-        destRect = destRect.translated(dx, dy).intersected(clipR);
-    const QRect sourceRect(destRect.translated(-dx, -dy));
+    QRect sourceRect = newRect.intersected(clipR);
     const QRect parentRect(rect & clipR);
 
     bool accelerateMove = accelEnv && isOpaque
@@ -951,7 +949,7 @@ void QWidgetPrivate::moveRect(const QRect &rect, int dx, int dy)
                           // No accelerate move for proxy widgets.
                           && !tlw->d_func()->extra->proxyWidget
 #endif
-                          && !isOverlapped(sourceRect) && !isOverlapped(destRect);
+                          && !isOverlapped(destRect) && (destRect == sourceRect || !isOverlapped(sourceRect));
 
     if (!accelerateMove) {
         QRegion parentR(effectiveRectFor(parentRect));
@@ -964,7 +962,10 @@ void QWidgetPrivate::moveRect(const QRect &rect, int dx, int dy)
         pd->invalidateBuffer(parentR);
         invalidateBuffer((newRect & clipR).translated(-data.crect.topLeft()));
     } else {
-
+        if (destRect.isValid())
+            destRect = destRect.translated(dx, dy).intersected(clipR);
+        sourceRect = destRect.translated(-dx, -dy);
+        
         QWidgetBackingStore *wbs = x->backingStore.data();
         QRegion childExpose(newRect & clipR);