selection filter.

hello friends,
here i have one query related to zoom session.
i have to 2 zoom sections(project and ra bill no).when i select the specified project in one zoom section.i want to get the specified "ra bill nos" according to the project in "ra bill zoom section".i use selection filter in field section but it is showing one default project with that project specified ra bills

here i use the code like this::

program section
before.program:
import("tpptc930.cprj",tpptc930.cprj)

field section

field.rabillno:
before.zoom:
export("project",project)
selection.filter:
query.extend.where.in.zoom("tpptc930.cprj=" & query.string(project))

thanks & regards
v.siva sai krishna