If you select Sort Records from the Records menu and it does not show that your records are sorted by DOF, then they are not sorted by DOF.
If you have FileMaker Advanced, select the script debugger tool and then click the column header to see what happens one step at a time. Only guess I can make from here is that maybe the entire blue background record is a button to sort by Stock number and so your mouse click may have "missed" the button to sort by DOF and clicked a button to sort by stock number.
You are completely right! The button for stock number extends way larger than the text box that actually says "stock number", so I was clicking that! I would have thought the button would simply take the place of the object. Is there a way to change the size the button occupies?
Fixed it! It was a problem with the position locks. Thanks again!