In mass update of leads, the fields for update is repeating every time "add field" is selected.

In leads we have enabled 2 fields , i.e. Owner and Rank for mass update. When trying mass update on leads, we select Owner and click on "Add field", the option for selecting Owner reappears when we try to select another field for mass update. In the ideal scenario, once Owner is selected then only Rank should come for selection.