1. Computer apparatus having a storage medium for merging software configurations, each configuration being formed of respective versions of software program artifacts, the apparatus comprising: a workspace providing a work environment in which to perform operations on a subject software configuration, the workspace identifying a change set of current changes being made to the subject software configuration; and a merge tool coupled to perform software configuration merges in the workspace, the workspace accumulating change sets in a merge of each artifact forming the subject software configuration and passing said accumulated change sets to the merge tool, and the merge tool responsively displays to a user an indication of the accumulated change sets such that the merge tool enables the user to make artifact merges in the context of substantially all previous merge decisions, wherein the merge tool accepts as input a list of accepted and rejected change sets recorded in respective artifact version logs, and returns as output display of an indication of additional change sets in the workspace that have been accepted and rejected by a user during current operation of the merge tool; and wherein the workspace further identifies deferred change sets, such that when the merge tool provides an indication change sets in the workspace that have been accepted and rejected an indication of additional change sets, if a previously incompletely merged artifact has deferred one of the additional change sets, the workspace enables the user to re-invoke the merge tool on the previously incompletely merged artifact.