--- a/content/html/content/src/nsHTMLSelectElement.cpp
+++ b/content/html/content/src/nsHTMLSelectElement.cpp
@@ -1212,18 +1212,17 @@ nsHTMLSelectElement::SetValue(const nsAS
   return rv;
 }
 
 
 NS_IMPL_BOOL_ATTR(nsHTMLSelectElement, Autofocus, autofocus)
 NS_IMPL_BOOL_ATTR(nsHTMLSelectElement, Disabled, disabled)
 NS_IMPL_BOOL_ATTR(nsHTMLSelectElement, Multiple, multiple)
 NS_IMPL_STRING_ATTR(nsHTMLSelectElement, Name, name)
-NS_IMPL_POSITIVE_INT_ATTR_DEFAULT_VALUE(nsHTMLSelectElement, Size, size,
-                                        GetDefaultSize())
+NS_IMPL_POSITIVE_INT_ATTR_DEFAULT_VALUE(nsHTMLSelectElement, Size, size, 0)
 NS_IMPL_INT_ATTR(nsHTMLSelectElement, TabIndex, tabindex)
 
 NS_IMETHODIMP
 nsHTMLSelectElement::Blur()
 {
   return nsGenericHTMLElement::Blur();
 }
 

--- a/content/html/content/src/nsHTMLSelectElement.h
+++ b/content/html/content/src/nsHTMLSelectElement.h
@@ -490,24 +490,16 @@ protected:
   void VerifyOptionsArray();
 #endif
 
   virtual PRBool AcceptAutofocus() const
   {
     return PR_TRUE;
   }
 
-  /**
-   * Helper method to get the default size.
-   */
-  PRInt32 GetDefaultSize() const
-  {
-    return HasAttr(kNameSpaceID_None, nsGkAtoms::multiple) ? 4 : 1;
-  }
-
   /** The options[] array */
   nsRefPtr<nsHTMLOptionCollection> mOptions;
   /** false if the parser is in the middle of adding children. */
   PRPackedBool    mIsDoneAddingChildren;
   /** true if our disabled state has changed from the default **/
   PRPackedBool    mDisabledChanged;
   /** true if child nodes are being added or removed.
    *  Used by nsSafeOptionListMutation.

--- a/content/html/content/test/test_bug551846.html
+++ b/content/html/content/test/test_bug551846.html
@@ -117,43 +117,43 @@ function checkSetSizeException(element)
     caught = true;
   }
   ok(!caught, "Setting an invalid size in the content attribute shouldn't throw an exception");
 
   // reverting to defalut
   element.removeAttribute('size');
 }
 
-function checkSizeWhenChangeMultiple(element)
+function checkSizeWhenChangeMultiple(element, aDefaultNonMultiple, aDefaultMultiple)
 {
   s.setAttribute('size', -1)
-  is(s.size, 1, "Size IDL attribute should be 1");
+  is(s.size, aDefaultNonMultiple, "Size IDL attribute should be 1");
 
   s.multiple = true;
-  is(s.size, 4, "Size IDL attribute should be 4");
+  is(s.size, aDefaultMultiple, "Size IDL attribute should be 4");
 
   is(s.getAttribute('size'), -1, "Size content attribute should be -1");
 
   s.setAttribute('size', -2);
-  is(s.size, 4, "Size IDL attribute should be 4");
+  is(s.size, aDefaultMultiple, "Size IDL attribute should be 4");
 
   s.multiple = false;
-  is(s.size, 1, "Size IDL attribute should be 1");
+  is(s.size, aDefaultNonMultiple, "Size IDL attribute should be 1");
 
   is(s.getAttribute('size'), -2, "Size content attribute should be -2");
 }
 
 var s = document.getElementById('s');
 
-checkSizeReflection(s, 1);
+checkSizeReflection(s, 0);
 checkSetSizeException(s);
 
 s.setAttribute('multiple', 'true');
-checkSizeReflection(s, 4);
+checkSizeReflection(s, 0);
 checkSetSizeException(s);
 s.removeAttribute('multiple');
 
-checkSizeWhenChangeMultiple(s);
+checkSizeWhenChangeMultiple(s, 0, 0);
 
 </script>
 </pre>
 </body>
 </html>