In previous versions of STEM, once you had drawn a graph (e.g., for a result with three scenarios) it was not possible to modify the graph directly. If you wanted to change the graph (e.g., add additional results or scenarios), you had to redraw the graph with updated selections, usually starting afresh, and then tediously reposition it on the screen manually.
A major improvement in STEM 7.5 is that you can now modify a graph directly in situ.