"Target" not filtering target items for RequestFilter.filterRequest event handler

Hi All,

I am using RequestFilter.filterRequest event handler to set up some header parameters. I would like apply these header paramaters to only certain requests. So when I give any input on "Target" column, script for RequestFilter.filterRequest event handler is not running at all. If I leave "Target" column empty, then all the requests are running and headers are attaching to all requests. 

What should be coded in "Target" column to apply headers only to specific requests/Test Steps. 

Thanks.