17. The article of manufacture of claim 12 , wherein the instructions to present the elements, facilitate the selection of the elements, and present the indication of the merging action to be taken comprise instructions to: present the elements of the first version in a first visual list; present the elements of the second version in a second visual list; annotate the elements of the first and second lists with specific visual marks that denote the element status, as one of new, changed, or conflict; annotate the elements of the first and second lists with specific visual marks that denote non-existing elements, including marks in the first list for elements that are deleted in the second list and marks in the second list for elements that are deleted in the first list; select all the elements of the first list automatically; and upon user selection of elements or non-existing elements in the second list, update the first list with specific visual marks that denote the merge action to be taken, as one of merge, remove, or replace.
18. The article of manufacture of claim 17 , wherein the instructions to take the indicated actions, thereby merging the first version with the second version, comprise instructions to: determine which new elements of the second list are selected, merge the corresponding element of the second version into the first design model version; determine which deleted elements of the second list are selected, remove the corresponding element from the first version; determine which changed or conflict elements of the second list are selected; and replace the corresponding element of the first version with the corresponding element of the second version.