Set Focus on subform/listbox record using main form criteria

[sandybam]

I have been asked to create a search form set up the following way:

The main form will consist of these fields: CaseNumber, CaseName, EeName. There will then be a subform or list box that will list all of the records in the entire database (which includes these fields). Once the user enters data into any one of the fields on the main form (or any combination of fields) the subform/list box will set focus on that record. I have been able to return only the record that coincides with the data entered into the main form but I have not been able to just set focus on the record as the user types in data into the main form. The department is set in their ways and wants this new database to look just like the old one. Any ideas?

Thank you!
Sandy