eg:

1. spell error on "tex"
 
   <xmltag>tex</xmltag>.

2. extract tex to one file to do spell checking.
   extract <xmltag> to other file.

   content of file 1:         tex 
   content of file 2: <xmltag>   </xmltag> 

3. check the content of file 1 :  tex --> text

4. after spell checking

   content of file 1:         text
   content of file 2: <xmltag>   </xmltag>

5. combine the content of this two file
   -produce new xml file that contain:

       <xmltag>text</xmltag>