With Profiles > Define and Highlight Elevation Profile the series of links to be included in the long section plot, can be defined in the same way as described for Profiles > Define and Show Elevation Profile. This menu option, however, does not automatically open the Quick Longsection window, but instead highlights (i.e. selects) the long section links in the model as shown below.
The user can then afterwards always open the Quick Longsection window (via Profiles > Show Defined Elevation Profile) to view/edit the long section plot.