It is possible to draw several longitudinal profiles at the same time on a same comparison plan with this option. If this button is selected, the longitudinal profile initially selected will appear by default. As many longitudinal profiles as, one wishes to add to the representation can then be inserted. The window shown below is then displayed when this command is activated:
As you can see, you have the option of configuring the Layer, Line Type and representation color of the corresponding longitudinal profile.