That is controlled in the RB-INCLUDE-RECORDS value. You probably have it set to "?" which displays a dialog box allowing the user to enter a filter expression or edit the filter specified in the report definition.
If you are using the PRINTRB interface, I believe RB-INCLUDE-RECORDS is the 5th value.
Obviously it's the RB-INCLUDE-RECORDS field for the table interface.
Check out Table 3-2 of the Report Builder Deployment Guide for the 5 value values and their meanings for RB-INCLUDE-RECORDS.
We typicall use "O" for override which then allows you to specify your own filter value in the RB-FILTER parameter. This gives you dynamic filtering from the code side.
Here's the link in the dyna-web for that table:
http://www.progress.com:6336/dynawe...webQuery=Table+3-2:+RB-INCLUDE-RECORDS+Values
HTH!