HS: Fix hs section set and display.

src/View/Geometry/PlotRKZ.py

@@ -299,7 +299,7 @@ class PlotRKZ(PamhyrPlot):
         for hs in lhs:
             if not hs.enabled:
                 continue
-            x = hs.input_rk
+            x = hs.input_section.rk
             if x is not None:
                 z_min = reach.get_z_min()
                 z_max = reach.get_z_max()