Fields can be mapped from one entity to another entity via the relationships form and the "Mappings" option. The first form shows the currently mapped fields. When the "New" option is selected, the "Create Field Mapping From (entity) to (entity)" form is displayed. Three columns are displayed: Name, Display Name and Type (Size) for each entity. The form opens but the column sizing and form sizing uses up only slightly more than 50% of the total screen, generally clipping the values so one may need to resize the column if there are fields with similar names. The resizing of columns has to be performed for each entity. After one selects a field from the source entity and one or more fields for the destination, the [OK] button is used to commit the change, and then the form goes away and one is back at the listing form. If one needs to map more than one field, they have to select the "New" option again and go through all of the same steps.

Recommendations: Open the form with better column sizes utilizing the full screen instead of only part of it.
Remove the [OK] button. Add a [SAVE] and a [SAVE+NEW] button. The [SAVE] option would be the same as the current [OK] button. The [SAVE+NEW] button would commit the current selection and clear the check boxes from both the source and destination entities but remain on the "Create Field Mapping" form so one doesn't have to re-open the form and re-size the columns if there is another field to map.

The current behavior is in the classic interface. The Unified Interface doesn't have the "Mapping" functionality yet.