[proFit-list] proFit 6.2.16 - drawing in a graph

[Spiderbat]

Hi! I'm still using proFit 6.2.12 on a very old computer. Presently, I would like to draw vertical lines in a scatter plot graph (the x-axis represents time in days and I would draw my lines to separate months). I tried to write a program to achieve my goal and did several experiments, but I haven't grasped yet howf the drawing environment works. In particular,  I believe that there are at least two systems of coordinates, one for the window where the graph resides, one for the graph, whose coordinates correspond to the values on the axes. Unfortunately, I didn't find any comprehensive explanation on this subject, as well, e. g., on the different role and purpose of 'curves' and 'shapes'. Could someone point me to some explicative material and/or examples on this topic?

TIA
Andrea Perego