1. A method of displaying changes to a data file comprising: associating an annotation with a programming module of a baseline file; displaying in a window of a graphical user interface the baseline file as a tree structure having a plurality of nodes, each node representing a programming module of the baseline file; and displaying the annotation proximate to the node that represents the programming module with which the annotation is associated, the annotation including at least one message indicative of a modification made to the baseline file by a contributor.