Blank or Null Value not displayed in Report Filter(Quick Filter)

Hello All,

I tried to filter the Null data in report (not in Query) but Null or Blank data is not dispalyed while selecting the values in quick filter.

As a work around i have replaced the Null value in to some other and filtered it, But I want to know why the bank or null value is not displayed

DB: Sql server 2005

Universe: UNX
BO version : 4.1

Kindly help me to understand why Null values is displayed in the Filter's List

Regards

Arun