Some of the have fields or field groups that can save more than one entry. These fields have a small button with four arrows on the right side of the field. If you hover over this button, the Record Navigator is displayed. The Record Navigator is inactive until you enter values into the field or fields for which it stores records. Once a value is saved, you can keep entering values in the same field.
When you hover over the Record Navigator button, the Record Navigator is displayed. Here, the Record Navigator is transparent because it is not yet storing any records.