Grid Box behavior

The process I'm looking for is similar to how it works in P0006. In that program, you can run a search, select a resultant row, modify the contents, click ok then cancel. At that point, the modified row will be in the list with the changes and the other rows ( which still match the search criteria ) will remain. If you click find, the modified row will be removed.

I'm unable to replicate this behavior. I'm able to get the modified row to display, but it shows the original values not the modified ones.