[Solved]drill through problem

[mrcool]

Hi Frnds,

               I have 4 prompts in the prompt page of child report.out of which 3 are cascading and the other is with static choices.
Iam using the parameter in the static prompt in the main query.For ex:
lets take parameter name as level.This parameter iam using in query not in filter
In query am using as case When ?level?='Month' then [xyz]
                                           when ?level?='YTD' then [pqr]
                                            else [abc]
                                            End
This is making my prompt required.Am using def value to make it as optional.
When Iam trying to drill to child  report from parent report Iam seeing the prompt page,prompting for values which I dnt want 2 c.
By analysing i hav found that level prompt is expecting some value,even when the def value is given.With out prompt page its working fine.problem is when am using prompt page.But i must use prompt page in child report.
Plz help me out frm this problem.

Thanks in advance