Advanced Search - Custom field search not working ( field belongs to custom group used for contribution )

Steps to be followed:
1. Create a custom group Used For: Contribution.
2. Add some custom fields eg Greeting (alphanumeric).
3. Make a contribution, also enter some data in those custom fields. eg 'Hello'.
4. Then goto advanced search, search with the data entered. eg 'Hello'. It should display the contact who has 'Hello' value.
But it displays all the contacts.