Well, Vertical Range determines what is shown in a section, so if the wall falls below the section's range, it won't show.
Also check that you have the layers visible that you want to see in the section.
If you want to see things in 3D (to make changes etc) you can also draw a marquee with bold outline around the elements and pick 'show selection in 3D'.
Erwin Edel, Project Lead, Leloup Architecten
www.leloup.nlArchiCAD 9-26NED FULL
Windows 10 Pro
Adobe Design Premium CS5