--- a/editor/libeditor/html/nsHTMLEditorStyle.cpp
+++ b/editor/libeditor/html/nsHTMLEditorStyle.cpp
@@ -870,19 +870,23 @@ nsresult nsHTMLEditor::RemoveStyleInside
                                                     &propertyValue,
                                                     false);
       // remove the node if it is a span or font, if its style attribute is
       // empty or absent, and if it does not have a class nor an id
       RemoveElementIfNoStyleOrIdOrClass(aNode);
     }
   }
 
-  if (aProperty == nsEditProperty::font &&    // or node is big or small and we are setting font size
+  if (!aChildrenOnly &&
+    (
+      (aProperty == nsEditProperty::font) &&    // or node is big or small and we are setting font size
       (nsHTMLEditUtils::IsBig(aNode) || nsHTMLEditUtils::IsSmall(aNode)) &&
-      aAttribute && aAttribute->LowerCaseEqualsLiteral("size")) {
+      (aAttribute && aAttribute->LowerCaseEqualsLiteral("size"))
+    )
+  ) {
     return RemoveContainer(aNode);  // if we are setting font size, remove any nested bigs and smalls
   }
   return NS_OK;
 }
 
 bool nsHTMLEditor::IsOnlyAttribute(nsIDOMNode *aNode, 
                                      const nsAString *aAttribute)
 {