diff -r 30342f40acbf -r e1bea15f9a39 webengine/osswebengine/WebCore/rendering/RenderObject.cpp
--- a/webengine/osswebengine/WebCore/rendering/RenderObject.cpp	Thu Jul 15 19:53:20 2010 +0300
+++ b/webengine/osswebengine/WebCore/rendering/RenderObject.cpp	Thu Aug 19 10:58:56 2010 +0300
@@ -2142,11 +2142,10 @@
     bool affectsParentBlock = false;
     RenderStyle::Diff d = RenderStyle::Equal;
     if (m_style) {
-        d = m_style->diff(style);
-
         // If our z-index changes value or our visibility changes,
         // we need to dirty our stacking context's z-order list.
         if (style) {
+            d = m_style->diff(style);
             if (m_style->visibility() != style->visibility() ||
                     m_style->zIndex() != style->zIndex() ||
                     m_style->hasAutoZIndex() != style->hasAutoZIndex())