--- a/layout/xul/base/src/nsBoxFrame.cpp
+++ b/layout/xul/base/src/nsBoxFrame.cpp
@@ -513,23 +513,28 @@ nsBoxFrame::GetInitialDirection(bool& aI
 
   // Now check the style system to see if we should invert aIsNormal.
   const nsStyleXUL* boxInfo = GetStyleXUL();
   if (boxInfo->mBoxDirection == NS_STYLE_BOX_DIRECTION_REVERSE)
     aIsNormal = !aIsNormal; // Invert our direction.
   
   // Now see if we have an attribute.  The attribute overrides
   // the style system value.
-  static nsIContent::AttrValuesArray strings[] =
-    {&nsGkAtoms::reverse, &nsGkAtoms::ltr, &nsGkAtoms::rtl, nsnull};
-  PRInt32 index = GetContent()->FindAttrValueIn(kNameSpaceID_None, nsGkAtoms::dir,
-      strings, eCaseMatters);
-  if (index >= 0) {
-    bool values[] = {!aIsNormal, true, false};
-    aIsNormal = values[index];
+  if (IsHorizontal()) {
+    static nsIContent::AttrValuesArray strings[] =
+      {&nsGkAtoms::reverse, &nsGkAtoms::ltr, &nsGkAtoms::rtl, nsnull};
+    PRInt32 index = GetContent()->FindAttrValueIn(kNameSpaceID_None, nsGkAtoms::dir,
+        strings, eCaseMatters);
+    if (index >= 0) {
+      bool values[] = {!aIsNormal, true, false};
+      aIsNormal = values[index];
+    }
+  } else if (GetContent()->AttrValueIs(kNameSpaceID_None, nsGkAtoms::dir,
+                                       nsGkAtoms::reverse, eCaseMatters)) {
+    aIsNormal = !aIsNormal;
   }
 }
 
 /* Returns true if it was set.
  */
 bool
 nsBoxFrame::GetInitialEqualSize(bool& aEqualSize)
 {