16. The method of claim 14 , further comprising the first shell automatically updating the first index when the content of the first active document is modified.
16. The method of claim 14 , further comprising the first shell automatically updating the first index when the content of the first active document is modified. 17. The method of claim 16 , further comprising sending a notification request to other shells when the first index is modified, to verify whether or not the other shells are similar to the first shell.