--- a/src/3rdparty/webkit/WebCore/rendering/RenderBoxModelObject.cpp	Fri Apr 16 15:50:13 2010 +0300
+++ b/src/3rdparty/webkit/WebCore/rendering/RenderBoxModelObject.cpp	Mon May 03 13:17:34 2010 +0300
@@ -557,6 +557,17 @@
     // Determine the background positioning area and set destRect to the background painting area.
     // destRect will be adjusted later if the background is non-repeating.
     bool fixedAttachment = fillLayer->attachment() == FixedBackgroundAttachment;
+
+#if ENABLE(FAST_MOBILE_SCROLLING)
+    if (view()->frameView() && view()->frameView()->canBlitOnScroll()) {
+        // As a side effect of an optimization to blit on scroll, we do not honor the CSS
+        // property "background-attachment: fixed" because it may result in rendering
+        // artifacts. Note, these artifacts only appear if we are blitting on scroll of
+        // a page that has fixed background images.
+        fixedAttachment = false;
+    }
+#endif
+
     if (!fixedAttachment) {
         destRect = IntRect(tx, ty, w, h);