Ted,
I tried to change your code for my fields/data source and it kept giving me an error.
My data source is named Jobs. Fields are job_no and job_name
My dropdown list is named ddl_jobno and the value and display is set to job_no.
My textbox is named tbox_jobname
Just to clarify...when a user selects the job_no from the dropdown list the job_name value appears in the textbox.
Your code was: ID[Customers = FilterName]
I entered this for my code: Job_No[ddl_JobNo = Job_Name]
Not sure what I'm doing wrong.