This post is the answer to a question in the comments of one of my earlier posts: https://enterprisesmartapps.wordpress.com/2011/12/13/birt-drop-group-header-property-and-table-border-lines/#comments.
Follow the link if you want more info on the drop property.
Miguel asks what the difference is between “Detail” and “All” as a value for the drop property. An example will show the difference.
In this example I have this very simple query that selects from the ClassicModels sample database:
select o.city, e.lastname from offices o, employees e where o.officecode = e.officecode order by o.officecode, e.lastname
Notice the grouping on the CITY field and that the field appears in the header as well as in the footer row.
So the difference is in the footer row. Drop All removes all occurrences of the CITY field beneath the header row, while Drop Detail only hides the CITY field in the detail section and still shows it in the footer row.