A field overlay is a copy of the field's properties. The data viewed through an origin field and its overlay field is the same.
When you overlay a field, you can change field properties such as Permissions, Default Value, Length, Associated Menu, Help Text, and Full Text MFS Category Name.
You cannot modify Layout, Display, Color, Font, and Highlight field properties by overlaying a field. To modify these properties, add the field to a view overlay where you want to change the field's layout or display properties. For information about adding a field to view overlay, see Adding-a-field-to-a-view-overlay.
Tip
- When a field is overlaid and that field is included on a join form, changes to the field’s properties must be reflected in the join form. If the join form is not overlaid or the join form field is not overlaid, does not have the correct repository for the change at the join form level.
To remedy this issue, the system automatically creates overlays for the join forms and fields whenever any change is made to an overlaid field in an origin form and the join overlays do not already exist. These overlays inherit all of the characteristics from the origin forms and fields. The system then propagates the property changes to the join field overlay. The creation of the overlays occurs in the background, and Developer Studio does not immediately show that the join form or field objects are overlaid until they are opened or until you refresh the form. When a field is overlaid and that field is included on a join form, the Object Granularity Level utility only compares the changes in FTS and Help Text properties for recommending field granularity level for the inherited field. For new fields on the base join form, the Object Granularity level utility compares the changes in all the properties for recommending field granularity level.
You can overlay granular portions of an object's field properties. For fields, there are two grains: Permissions and Others.
Overlay field property
For information about the overlay types that you can apply to a field's property, see Granular-overlays.