diff --git a/mozilla/content/base/src/nsStyleContext.cpp b/mozilla/content/base/src/nsStyleContext.cpp
index 232805daf44..d1200c9093d 100644
--- a/mozilla/content/base/src/nsStyleContext.cpp
+++ b/mozilla/content/base/src/nsStyleContext.cpp
@@ -553,8 +553,11 @@ void StylePositionImpl::ResetFrom(const nsStylePosition* aParent, nsIPresContext
 {
   // positioning values not inherited
   mPosition = NS_STYLE_POSITION_NORMAL;
-  mLeftOffset.SetAutoValue();
-  mTopOffset.SetAutoValue();
+  nsStyleCoord  autoCoord(eStyleUnit_Auto);
+  mOffset.SetLeft(autoCoord);
+  mOffset.SetTop(autoCoord);
+  mOffset.SetRight(autoCoord);
+  mOffset.SetBottom(autoCoord);
   mWidth.SetAutoValue();
   mMinWidth.SetCoordValue(0);
   mMaxWidth.Reset();
diff --git a/mozilla/content/html/style/src/nsCSSLayout.cpp b/mozilla/content/html/style/src/nsCSSLayout.cpp
index bfed185e18a..326284ef60f 100644
--- a/mozilla/content/html/style/src/nsCSSLayout.cpp
+++ b/mozilla/content/html/style/src/nsCSSLayout.cpp
@@ -98,23 +98,23 @@ nsCSSLayout::RelativePositionChildren(nsIPresContext* aCX,
     if (NS_STYLE_POSITION_RELATIVE == kidPosition->mPosition) {
       kid->GetOrigin(origin);
       nscoord dx = 0;
-      switch (kidPosition->mLeftOffset.GetUnit()) {
+      switch (kidPosition->mOffset.GetLeftUnit()) {
       case eStyleUnit_Percent:
         printf("XXX: not yet implemented: % relative position\n");
       case eStyleUnit_Auto:
         break;
       case eStyleUnit_Coord:
-        dx = kidPosition->mLeftOffset.GetCoordValue();
+        dx = kidPosition->mOffset.GetLeft().GetCoordValue();
         break;
       }
       nscoord dy = 0;
-      switch (kidPosition->mTopOffset.GetUnit()) {
+      switch (kidPosition->mOffset.GetTopUnit()) {
       case eStyleUnit_Percent:
         printf("XXX: not yet implemented: % relative position\n");
       case eStyleUnit_Auto:
         break;
       case eStyleUnit_Coord:
-        dy = kidPosition->mTopOffset.GetCoordValue();
+        dy = kidPosition->mOffset.GetTop().GetCoordValue();
         break;
       }
       kid->MoveTo(origin.x + dx, origin.y + dy);
diff --git a/mozilla/content/html/style/src/nsCSSStyleRule.cpp b/mozilla/content/html/style/src/nsCSSStyleRule.cpp
index 58a6394dae4..59105c0055d 100644
--- a/mozilla/content/html/style/src/nsCSSStyleRule.cpp
+++ b/mozilla/content/html/style/src/nsCSSStyleRule.cpp
@@ -1813,9 +1813,19 @@ void MapDeclarationInto(nsICSSDeclaration* aDeclaration,
 
         // box offsets: length, percent, auto, inherit
         if (nsnull != ourPosition->mOffset) {
-          SetCoord(ourPosition->mOffset->mTop, position->mTopOffset, SETCOORD_LPAH, font, aPresContext);
-          // XXX right bottom
-          SetCoord(ourPosition->mOffset->mLeft, position->mLeftOffset, SETCOORD_LPAH, font, aPresContext);
+          nsStyleCoord  coord;
+          if (SetCoord(ourPosition->mOffset->mTop, coord, SETCOORD_LPAH, font, aPresContext)) {
+            position->mOffset.SetTop(coord);            
+          }
+          if (SetCoord(ourPosition->mOffset->mRight, coord, SETCOORD_LPAH, font, aPresContext)) {
+            position->mOffset.SetRight(coord);            
+          }
+          if (SetCoord(ourPosition->mOffset->mBottom, coord, SETCOORD_LPAH, font, aPresContext)) {
+            position->mOffset.SetBottom(coord);
+          }
+          if (SetCoord(ourPosition->mOffset->mLeft, coord, SETCOORD_LPAH, font, aPresContext)) {
+            position->mOffset.SetLeft(coord);
+          }
         }
 
         SetCoord(ourPosition->mWidth, position->mWidth, SETCOORD_LPAH, font, aPresContext);
diff --git a/mozilla/layout/base/public/nsIStyleContext.h b/mozilla/layout/base/public/nsIStyleContext.h
index b16ff4e13c9..f070edea6e2 100644
--- a/mozilla/layout/base/public/nsIStyleContext.h
+++ b/mozilla/layout/base/public/nsIStyleContext.h
@@ -124,8 +124,7 @@ protected:
 struct nsStylePosition : public nsStyleStruct {
   PRUint8   mPosition;                  // [reset] see nsStyleConsts.h
 
-  nsStyleCoord  mLeftOffset;            // [reset] 
-  nsStyleCoord  mTopOffset;             // [reset] 
+  nsStyleSides  mOffset;                // [reset]
   nsStyleCoord  mWidth;                 // [reset] coord, percent, auto, inherit
   nsStyleCoord  mMinWidth;              // [reset] coord, percent, inherit
   nsStyleCoord  mMaxWidth;              // [reset] coord, percent, null, inherit
diff --git a/mozilla/layout/base/src/nsStyleContext.cpp b/mozilla/layout/base/src/nsStyleContext.cpp
index 232805daf44..d1200c9093d 100644
--- a/mozilla/layout/base/src/nsStyleContext.cpp
+++ b/mozilla/layout/base/src/nsStyleContext.cpp
@@ -553,8 +553,11 @@ void StylePositionImpl::ResetFrom(const nsStylePosition* aParent, nsIPresContext
 {
   // positioning values not inherited
   mPosition = NS_STYLE_POSITION_NORMAL;
-  mLeftOffset.SetAutoValue();
-  mTopOffset.SetAutoValue();
+  nsStyleCoord  autoCoord(eStyleUnit_Auto);
+  mOffset.SetLeft(autoCoord);
+  mOffset.SetTop(autoCoord);
+  mOffset.SetRight(autoCoord);
+  mOffset.SetBottom(autoCoord);
   mWidth.SetAutoValue();
   mMinWidth.SetCoordValue(0);
   mMaxWidth.Reset();
diff --git a/mozilla/layout/generic/nsAreaFrame.cpp b/mozilla/layout/generic/nsAreaFrame.cpp
index c2096752799..17bcf2b54ce 100644
--- a/mozilla/layout/generic/nsAreaFrame.cpp
+++ b/mozilla/layout/generic/nsAreaFrame.cpp
@@ -530,8 +530,8 @@ nsAreaFrame::ReflowAbsoluteItems(nsIPresContext& aPresContext,
 #endif
       // We need to place the frame if the left-offset or the top-offset are
       // auto or a percentage
-      if ((eStyleUnit_Coord != position->mLeftOffset.GetUnit()) ||
-          (eStyleUnit_Coord != position->mTopOffset.GetUnit())) {
+      if ((eStyleUnit_Coord != position->mOffset.GetLeftUnit()) ||
+          (eStyleUnit_Coord != position->mOffset.GetTopUnit())) {
         placeFrame = PR_TRUE;
       }
 
@@ -622,8 +622,8 @@ void nsAreaFrame::ComputeAbsoluteFrameBounds(nsIPresContext&          aPresConte
   // If either the left or top are 'auto' then get the offset of the anchor
   // frame from this frame
   nsPoint offset(0, 0);
-  if ((eStyleUnit_Auto == aPosition->mLeftOffset.GetUnit()) ||
-      (eStyleUnit_Auto == aPosition->mTopOffset.GetUnit())) {
+  if ((eStyleUnit_Auto == aPosition->mOffset.GetLeftUnit()) ||
+      (eStyleUnit_Auto == aPosition->mOffset.GetTopUnit())) {
     // Get the placeholder frame
     nsIFrame*     placeholderFrame;
     nsIPresShell* presShell = aPresContext.GetShell();
@@ -638,42 +638,46 @@ void nsAreaFrame::ComputeAbsoluteFrameBounds(nsIPresContext&          aPresConte
   }
 
   // left-offset
-  if (eStyleUnit_Auto == aPosition->mLeftOffset.GetUnit()) {
+  if (eStyleUnit_Auto == aPosition->mOffset.GetLeftUnit()) {
     // Use the current x-offset of the anchor frame translated into our
     // coordinate space
     aRect.x = offset.x;
-  } else if (eStyleUnit_Coord == aPosition->mLeftOffset.GetUnit()) {
-    aRect.x = aPosition->mLeftOffset.GetCoordValue();
+  } else if (eStyleUnit_Coord == aPosition->mOffset.GetLeftUnit()) {
+    nsStyleCoord  coord;
+    aRect.x = aPosition->mOffset.GetLeft(coord).GetCoordValue();
   } else {
-    NS_ASSERTION(eStyleUnit_Percent == aPosition->mLeftOffset.GetUnit(),
+    NS_ASSERTION(eStyleUnit_Percent == aPosition->mOffset.GetLeftUnit(),
                  "unexpected offset type");
     // Percentage values refer to the width of the containing block. If the
     // width is unconstrained then just use 0
     if (NS_UNCONSTRAINEDSIZE == aReflowState.availableWidth) {
       aRect.x = 0;
     } else {
+      nsStyleCoord  coord;
       aRect.x = (nscoord)((float)aReflowState.availableWidth *
-                          aPosition->mLeftOffset.GetPercentValue());
+                          aPosition->mOffset.GetLeft(coord).GetPercentValue());
     }
   }
 
   // top-offset
-  if (eStyleUnit_Auto == aPosition->mTopOffset.GetUnit()) {
+  if (eStyleUnit_Auto == aPosition->mOffset.GetTopUnit()) {
     // Use the current y-offset of the anchor frame translated into our
     // coordinate space
     aRect.y = offset.y;
-  } else if (eStyleUnit_Coord == aPosition->mTopOffset.GetUnit()) {
-    aRect.y = aPosition->mTopOffset.GetCoordValue();
+  } else if (eStyleUnit_Coord == aPosition->mOffset.GetTopUnit()) {
+    nsStyleCoord  coord;
+    aRect.y = aPosition->mOffset.GetTop(coord).GetCoordValue();
   } else {
-    NS_ASSERTION(eStyleUnit_Percent == aPosition->mTopOffset.GetUnit(),
+    NS_ASSERTION(eStyleUnit_Percent == aPosition->mOffset.GetTopUnit(),
                  "unexpected offset type");
     // Percentage values refer to the height of the containing block. If the
     // height is unconstrained then interpret it like 'auto'
     if (NS_UNCONSTRAINEDSIZE == aReflowState.availableHeight) {
       aRect.y = offset.y;
     } else {
+      nsStyleCoord  coord;
       aRect.y = (nscoord)((float)aReflowState.availableHeight *
-                          aPosition->mTopOffset.GetPercentValue());
+                          aPosition->mOffset.GetTop(coord).GetPercentValue());
     }
   }
 
diff --git a/mozilla/layout/generic/nsBlockReflowContext.cpp b/mozilla/layout/generic/nsBlockReflowContext.cpp
index 01b9de1977b..8903633df77 100644
--- a/mozilla/layout/generic/nsBlockReflowContext.cpp
+++ b/mozilla/layout/generic/nsBlockReflowContext.cpp
@@ -396,26 +396,28 @@ nsBlockReflowContext::ComputeRelativePosition(nsIFrame* aFrame,
                                               const nsStylePosition* aStylePos,
                                               nscoord& aX, nscoord& aY)
 {
+  nsStyleCoord coord;
+  
   nscoord dx = 0;
-  switch (aStylePos->mLeftOffset.GetUnit()) {
+  switch (aStylePos->mOffset.GetLeftUnit()) {
   case eStyleUnit_Percent:
     printf("XXX: not yet implemented: % relative position\n");
   case eStyleUnit_Auto:
     break;
   case eStyleUnit_Coord:
-    dx = aStylePos->mLeftOffset.GetCoordValue();
+    dx = aStylePos->mOffset.GetLeft(coord).GetCoordValue();
     break;
   }
   aX += dx;
 
   nscoord dy = 0;
-  switch (aStylePos->mTopOffset.GetUnit()) {
+  switch (aStylePos->mOffset.GetTopUnit()) {
   case eStyleUnit_Percent:
     printf("XXX: not yet implemented: % relative position\n");
   case eStyleUnit_Auto:
     break;
   case eStyleUnit_Coord:
-    dy = aStylePos->mTopOffset.GetCoordValue();
+    dy = aStylePos->mOffset.GetTop(coord).GetCoordValue();
     break;
   }
   aY += dy;
diff --git a/mozilla/layout/html/base/src/nsAreaFrame.cpp b/mozilla/layout/html/base/src/nsAreaFrame.cpp
index c2096752799..17bcf2b54ce 100644
--- a/mozilla/layout/html/base/src/nsAreaFrame.cpp
+++ b/mozilla/layout/html/base/src/nsAreaFrame.cpp
@@ -530,8 +530,8 @@ nsAreaFrame::ReflowAbsoluteItems(nsIPresContext& aPresContext,
 #endif
       // We need to place the frame if the left-offset or the top-offset are
       // auto or a percentage
-      if ((eStyleUnit_Coord != position->mLeftOffset.GetUnit()) ||
-          (eStyleUnit_Coord != position->mTopOffset.GetUnit())) {
+      if ((eStyleUnit_Coord != position->mOffset.GetLeftUnit()) ||
+          (eStyleUnit_Coord != position->mOffset.GetTopUnit())) {
         placeFrame = PR_TRUE;
       }
 
@@ -622,8 +622,8 @@ void nsAreaFrame::ComputeAbsoluteFrameBounds(nsIPresContext&          aPresConte
   // If either the left or top are 'auto' then get the offset of the anchor
   // frame from this frame
   nsPoint offset(0, 0);
-  if ((eStyleUnit_Auto == aPosition->mLeftOffset.GetUnit()) ||
-      (eStyleUnit_Auto == aPosition->mTopOffset.GetUnit())) {
+  if ((eStyleUnit_Auto == aPosition->mOffset.GetLeftUnit()) ||
+      (eStyleUnit_Auto == aPosition->mOffset.GetTopUnit())) {
     // Get the placeholder frame
     nsIFrame*     placeholderFrame;
     nsIPresShell* presShell = aPresContext.GetShell();
@@ -638,42 +638,46 @@ void nsAreaFrame::ComputeAbsoluteFrameBounds(nsIPresContext&          aPresConte
   }
 
   // left-offset
-  if (eStyleUnit_Auto == aPosition->mLeftOffset.GetUnit()) {
+  if (eStyleUnit_Auto == aPosition->mOffset.GetLeftUnit()) {
     // Use the current x-offset of the anchor frame translated into our
     // coordinate space
     aRect.x = offset.x;
-  } else if (eStyleUnit_Coord == aPosition->mLeftOffset.GetUnit()) {
-    aRect.x = aPosition->mLeftOffset.GetCoordValue();
+  } else if (eStyleUnit_Coord == aPosition->mOffset.GetLeftUnit()) {
+    nsStyleCoord  coord;
+    aRect.x = aPosition->mOffset.GetLeft(coord).GetCoordValue();
   } else {
-    NS_ASSERTION(eStyleUnit_Percent == aPosition->mLeftOffset.GetUnit(),
+    NS_ASSERTION(eStyleUnit_Percent == aPosition->mOffset.GetLeftUnit(),
                  "unexpected offset type");
     // Percentage values refer to the width of the containing block. If the
     // width is unconstrained then just use 0
     if (NS_UNCONSTRAINEDSIZE == aReflowState.availableWidth) {
       aRect.x = 0;
     } else {
+      nsStyleCoord  coord;
       aRect.x = (nscoord)((float)aReflowState.availableWidth *
-                          aPosition->mLeftOffset.GetPercentValue());
+                          aPosition->mOffset.GetLeft(coord).GetPercentValue());
     }
   }
 
   // top-offset
-  if (eStyleUnit_Auto == aPosition->mTopOffset.GetUnit()) {
+  if (eStyleUnit_Auto == aPosition->mOffset.GetTopUnit()) {
     // Use the current y-offset of the anchor frame translated into our
     // coordinate space
     aRect.y = offset.y;
-  } else if (eStyleUnit_Coord == aPosition->mTopOffset.GetUnit()) {
-    aRect.y = aPosition->mTopOffset.GetCoordValue();
+  } else if (eStyleUnit_Coord == aPosition->mOffset.GetTopUnit()) {
+    nsStyleCoord  coord;
+    aRect.y = aPosition->mOffset.GetTop(coord).GetCoordValue();
   } else {
-    NS_ASSERTION(eStyleUnit_Percent == aPosition->mTopOffset.GetUnit(),
+    NS_ASSERTION(eStyleUnit_Percent == aPosition->mOffset.GetTopUnit(),
                  "unexpected offset type");
     // Percentage values refer to the height of the containing block. If the
     // height is unconstrained then interpret it like 'auto'
     if (NS_UNCONSTRAINEDSIZE == aReflowState.availableHeight) {
       aRect.y = offset.y;
     } else {
+      nsStyleCoord  coord;
       aRect.y = (nscoord)((float)aReflowState.availableHeight *
-                          aPosition->mTopOffset.GetPercentValue());
+                          aPosition->mOffset.GetTop(coord).GetPercentValue());
     }
   }
 
diff --git a/mozilla/layout/html/base/src/nsBlockReflowContext.cpp b/mozilla/layout/html/base/src/nsBlockReflowContext.cpp
index 01b9de1977b..8903633df77 100644
--- a/mozilla/layout/html/base/src/nsBlockReflowContext.cpp
+++ b/mozilla/layout/html/base/src/nsBlockReflowContext.cpp
@@ -396,26 +396,28 @@ nsBlockReflowContext::ComputeRelativePosition(nsIFrame* aFrame,
                                               const nsStylePosition* aStylePos,
                                               nscoord& aX, nscoord& aY)
 {
+  nsStyleCoord coord;
+  
   nscoord dx = 0;
-  switch (aStylePos->mLeftOffset.GetUnit()) {
+  switch (aStylePos->mOffset.GetLeftUnit()) {
   case eStyleUnit_Percent:
     printf("XXX: not yet implemented: % relative position\n");
   case eStyleUnit_Auto:
     break;
   case eStyleUnit_Coord:
-    dx = aStylePos->mLeftOffset.GetCoordValue();
+    dx = aStylePos->mOffset.GetLeft(coord).GetCoordValue();
     break;
   }
   aX += dx;
 
   nscoord dy = 0;
-  switch (aStylePos->mTopOffset.GetUnit()) {
+  switch (aStylePos->mOffset.GetTopUnit()) {
   case eStyleUnit_Percent:
     printf("XXX: not yet implemented: % relative position\n");
   case eStyleUnit_Auto:
     break;
   case eStyleUnit_Coord:
-    dy = aStylePos->mTopOffset.GetCoordValue();
+    dy = aStylePos->mOffset.GetTop(coord).GetCoordValue();
     break;
   }
   aY += dy;
diff --git a/mozilla/layout/html/base/src/nsInlineReflow.cpp b/mozilla/layout/html/base/src/nsInlineReflow.cpp
index 0f27307be85..b8cf1b050fc 100644
--- a/mozilla/layout/html/base/src/nsInlineReflow.cpp
+++ b/mozilla/layout/html/base/src/nsInlineReflow.cpp
@@ -985,24 +985,25 @@ nsInlineReflow::RelativePositionFrames(nsRect& aCombinedArea)
                       (const nsStyleStruct*&)kidPosition);
     if (NS_STYLE_POSITION_RELATIVE == kidPosition->mPosition) {
       kid->GetOrigin(origin);
+      nsStyleCoord coord;
       nscoord dx = 0;
-      switch (kidPosition->mLeftOffset.GetUnit()) {
+      switch (kidPosition->mOffset.GetLeftUnit()) {
       case eStyleUnit_Percent:
         printf("XXX: not yet implemented: % relative position\n");
       case eStyleUnit_Auto:
         break;
       case eStyleUnit_Coord:
-        dx = kidPosition->mLeftOffset.GetCoordValue();
+        dx = kidPosition->mOffset.GetLeft(coord).GetCoordValue();
         break;
       }
       nscoord dy = 0;
-      switch (kidPosition->mTopOffset.GetUnit()) {
+      switch (kidPosition->mOffset.GetTopUnit()) {
       case eStyleUnit_Percent:
         printf("XXX: not yet implemented: % relative position\n");
       case eStyleUnit_Auto:
         break;
       case eStyleUnit_Coord:
-        dy = kidPosition->mTopOffset.GetCoordValue();
+        dy = kidPosition->mOffset.GetTop(coord).GetCoordValue();
         break;
       }
       kid->MoveTo(origin.x + dx, origin.y + dy);
diff --git a/mozilla/layout/html/content/src/nsHTMLLayerElement.cpp b/mozilla/layout/html/content/src/nsHTMLLayerElement.cpp
index a8c13f75266..3253aedbe32 100644
--- a/mozilla/layout/html/content/src/nsHTMLLayerElement.cpp
+++ b/mozilla/layout/html/content/src/nsHTMLLayerElement.cpp
@@ -216,14 +216,14 @@ MapAttributesInto(nsIHTMLAttributes* aAttributes,
     aAttributes->GetAttribute(nsHTMLAtoms::left, value);
     if (value.GetUnit() == eHTMLUnit_Pixel) {
       nscoord twips = NSIntPixelsToTwips(value.GetPixelValue(), p2t);
-      position->mLeftOffset.SetCoordValue(twips);
+      position->mOffset.SetLeft(nsStyleCoord(twips));
     }
 
     // Top
     aAttributes->GetAttribute(nsHTMLAtoms::top, value);
     if (value.GetUnit() == eHTMLUnit_Pixel) {
       nscoord twips = NSIntPixelsToTwips(value.GetPixelValue(), p2t);
-      position->mTopOffset.SetCoordValue(twips);
+      position->mOffset.SetTop(nsStyleCoord(twips));
     }
 
     // Width
diff --git a/mozilla/layout/html/style/src/nsCSSLayout.cpp b/mozilla/layout/html/style/src/nsCSSLayout.cpp
index bfed185e18a..326284ef60f 100644
--- a/mozilla/layout/html/style/src/nsCSSLayout.cpp
+++ b/mozilla/layout/html/style/src/nsCSSLayout.cpp
@@ -98,23 +98,23 @@ nsCSSLayout::RelativePositionChildren(nsIPresContext* aCX,
     if (NS_STYLE_POSITION_RELATIVE == kidPosition->mPosition) {
       kid->GetOrigin(origin);
       nscoord dx = 0;
-      switch (kidPosition->mLeftOffset.GetUnit()) {
+      switch (kidPosition->mOffset.GetLeftUnit()) {
       case eStyleUnit_Percent:
         printf("XXX: not yet implemented: % relative position\n");
       case eStyleUnit_Auto:
         break;
       case eStyleUnit_Coord:
-        dx = kidPosition->mLeftOffset.GetCoordValue();
+        dx = kidPosition->mOffset.GetLeft().GetCoordValue();
         break;
       }
       nscoord dy = 0;
-      switch (kidPosition->mTopOffset.GetUnit()) {
+      switch (kidPosition->mOffset.GetTopUnit()) {
       case eStyleUnit_Percent:
         printf("XXX: not yet implemented: % relative position\n");
       case eStyleUnit_Auto:
         break;
       case eStyleUnit_Coord:
-        dy = kidPosition->mTopOffset.GetCoordValue();
+        dy = kidPosition->mOffset.GetTop().GetCoordValue();
         break;
       }
       kid->MoveTo(origin.x + dx, origin.y + dy);
diff --git a/mozilla/layout/html/style/src/nsCSSStyleRule.cpp b/mozilla/layout/html/style/src/nsCSSStyleRule.cpp
index 58a6394dae4..59105c0055d 100644
--- a/mozilla/layout/html/style/src/nsCSSStyleRule.cpp
+++ b/mozilla/layout/html/style/src/nsCSSStyleRule.cpp
@@ -1813,9 +1813,19 @@ void MapDeclarationInto(nsICSSDeclaration* aDeclaration,
 
         // box offsets: length, percent, auto, inherit
         if (nsnull != ourPosition->mOffset) {
-          SetCoord(ourPosition->mOffset->mTop, position->mTopOffset, SETCOORD_LPAH, font, aPresContext);
-          // XXX right bottom
-          SetCoord(ourPosition->mOffset->mLeft, position->mLeftOffset, SETCOORD_LPAH, font, aPresContext);
+          nsStyleCoord  coord;
+          if (SetCoord(ourPosition->mOffset->mTop, coord, SETCOORD_LPAH, font, aPresContext)) {
+            position->mOffset.SetTop(coord);            
+          }
+          if (SetCoord(ourPosition->mOffset->mRight, coord, SETCOORD_LPAH, font, aPresContext)) {
+            position->mOffset.SetRight(coord);            
+          }
+          if (SetCoord(ourPosition->mOffset->mBottom, coord, SETCOORD_LPAH, font, aPresContext)) {
+            position->mOffset.SetBottom(coord);
+          }
+          if (SetCoord(ourPosition->mOffset->mLeft, coord, SETCOORD_LPAH, font, aPresContext)) {
+            position->mOffset.SetLeft(coord);
+          }
         }
 
         SetCoord(ourPosition->mWidth, position->mWidth, SETCOORD_LPAH, font, aPresContext);
diff --git a/mozilla/layout/style/nsCSSStyleRule.cpp b/mozilla/layout/style/nsCSSStyleRule.cpp
index 58a6394dae4..59105c0055d 100644
--- a/mozilla/layout/style/nsCSSStyleRule.cpp
+++ b/mozilla/layout/style/nsCSSStyleRule.cpp
@@ -1813,9 +1813,19 @@ void MapDeclarationInto(nsICSSDeclaration* aDeclaration,
 
         // box offsets: length, percent, auto, inherit
         if (nsnull != ourPosition->mOffset) {
-          SetCoord(ourPosition->mOffset->mTop, position->mTopOffset, SETCOORD_LPAH, font, aPresContext);
-          // XXX right bottom
-          SetCoord(ourPosition->mOffset->mLeft, position->mLeftOffset, SETCOORD_LPAH, font, aPresContext);
+          nsStyleCoord  coord;
+          if (SetCoord(ourPosition->mOffset->mTop, coord, SETCOORD_LPAH, font, aPresContext)) {
+            position->mOffset.SetTop(coord);            
+          }
+          if (SetCoord(ourPosition->mOffset->mRight, coord, SETCOORD_LPAH, font, aPresContext)) {
+            position->mOffset.SetRight(coord);            
+          }
+          if (SetCoord(ourPosition->mOffset->mBottom, coord, SETCOORD_LPAH, font, aPresContext)) {
+            position->mOffset.SetBottom(coord);
+          }
+          if (SetCoord(ourPosition->mOffset->mLeft, coord, SETCOORD_LPAH, font, aPresContext)) {
+            position->mOffset.SetLeft(coord);
+          }
         }
 
         SetCoord(ourPosition->mWidth, position->mWidth, SETCOORD_LPAH, font, aPresContext);
diff --git a/mozilla/layout/style/nsStyleContext.cpp b/mozilla/layout/style/nsStyleContext.cpp
index 232805daf44..d1200c9093d 100644
--- a/mozilla/layout/style/nsStyleContext.cpp
+++ b/mozilla/layout/style/nsStyleContext.cpp
@@ -553,8 +553,11 @@ void StylePositionImpl::ResetFrom(const nsStylePosition* aParent, nsIPresContext
 {
   // positioning values not inherited
   mPosition = NS_STYLE_POSITION_NORMAL;
-  mLeftOffset.SetAutoValue();
-  mTopOffset.SetAutoValue();
+  nsStyleCoord  autoCoord(eStyleUnit_Auto);
+  mOffset.SetLeft(autoCoord);
+  mOffset.SetTop(autoCoord);
+  mOffset.SetRight(autoCoord);
+  mOffset.SetBottom(autoCoord);
   mWidth.SetAutoValue();
   mMinWidth.SetCoordValue(0);
   mMaxWidth.Reset();