EntityOpenCompositionAction is an entity picker action designed to open an editor screen for the one-to-one composition entity selected in the entity picker. If there is no linked entity at the moment (for example, the field is empty), a new instance is created and saved by the edit screen afterward.

The action is implemented by the io.jmix.ui.action.entitypicker.EntityOpenCompositionAction class and should be defined in XML using type="entity_openComposition" action’s attribute. The action parameters are the same as for EntityOpenAction.