Domain Index Online Rebuild Issue

Hi,

I was asked to recreate a domain index and thought that I can rebuild it online.

I thought I just can do an -> alter index MYINDEX rebuild online;  but it didn't seem to do what I expected.

e.g.

create table mytable(id number primary key, docs clob); 
insert into mytable values(111555,'this text will be indexed');
insert into mytable values(111556,'this is a default datastore example');
commit;
create index myindex on mytable(docs) 
 indextype is ctxsys.context 
 parameters ('DATASTORE CTXSYS.DEFAULT_DATASTORE');  
select index_name, parameters from dba_indexes where index_name = 'MYINDEX';  
--MYINDEX	DATASTORE CTXSYS.DEFAULT_DATASTORE
alter index MYINDEX rebuild online;  
select index_name, parameters from dba_indexes where index_name = 'MYINDEX';
--MYINDEX	(parameters colum is empty?)