16. The system of claim 15 wherein the lines within at least one expandable container image are solid and the lines within another expandable container image are dashed.
16. The system of claim 15 wherein the lines within at least one expandable container image are solid and the lines within another expandable container image are dashed. 17. The system of claim 16 wherein said format element includes a line merge element wherein an area on the display screen defined by two overlapping expandable container images displays the lines unique to the two overlapping expandable container images.