Empty value and connectable webpart...

[Jéjé]

Hi,

I've 2 webparts connected:
the first is a form where the user can type a customer name and/or a
customer ID (or partial name or partial ID)

then I display the list of the customers returned from my database.
No problem.

But, If I search a name like "john", then I clear the name and I fill the
customerid (like ALFKI), then my data view webpart keep the name "John" in
its filter!!!
so the result is a filtered list on the name AND the ID !

I must put a space in the name field of my form to insure that an empty
value is send to my result webpart!

is it normal?
how to force sharepoint to send blank or empty values?

thanks.

Jerome.