[TYPO3-english] How to extend the indexed_search

[Vikas]

Hi all,

I am not able to xclass/extend * tx_indexedsearch *class of* 
**class.tx_indexedsearch.php* file in the indexed_search extension.

But,  if i add this line:

  /global $TYPO3_CONF_VARS;/

in the file *class.tx_indexedsearch.php*, then i can successfully extend 
the class.

Can anybody tell me that, is this a bug in indexed_search or i am 
missing something?

Thanks in advance,
Vikas