Such a confirmation popover is only supported on actions without an action parameter dialog.
To display a confirmation popover, add the IsActionCritical annotation to your action as shown below:
XML Annotation
<Annotations Target="GWSAMPLE_BASIC.GWSAMPLE_BASIC_Entities/RegenerateAllData">
<Annotation Term="com.sap.vocabularies.Common.v1.IsActionCritical" Bool="true"/>
</Annotations>ABAP CDS Annotation
No ABAP CDS annotation sample is available. Please use the local XML annotation.
CAP CDS Annotation
annotate GWSAMPLE_BASIC.RegenerateAllData with @(
Common.IsActionCritical : true
); CDS
Annotation