Briefly, in accordance with one embodiment of the invention, a form author may declaratively state a condition under which a break event may occur to insert a break between data items in a list of data items. Optionally, formatting, a leader subform, and/or a trailer subform may be inserted between the data items in the event the condition is satisfied. Such a declarative condition may be introduced into an XFA template specification. A condition that may be evaluated may include mathematical operation, a Boolean expression, an integer expression, a floating point expression, a string expression, and/or a data item evaluation. A new layout of the list of data items may be implemented without transformation of the original layout of the list of data items wherein the list of data items may revert to the original layout of the list of data items, for example after performing an operation on the new layout of the list of data items.