Dear all,how could one manage to select really all records of the resultset of e.g. an advanced search and not only all records on the (first, second) page with the select all checkbox? To select "display all records" on one page first is not an option.Thanks

Since you always need to work with the whole data set there is no need to make user select any records. Simply make this button to process all search results.I would suggest to use BeforeSQLQuery event to save SQL query or WHERE clause in session variable and then use this session variable to access the whole data set in your button's OnServer code.