I notice that when I select between polysurfaces so the Selection Menu comes up, the Isocurves show-up as well. When I make a clear selection on a single polysurface, they don’t.
SetDisplayMode is set to Shaded. On my Shaded options the Isocurves are set to Off.
(For me personally it would be very useful if the Isocurves would be visible when an object is selected, even if they are switched off from display modes.)
I copy-paste the polysurfaces in a new file so I could put it on the forum and I see another problem:
In the new file SetDisplayMode is set to Shaded, SetObjectDisplayMode is set to UseView but they show up as Wireframe.
So, I attached the file below if you would like to check:
(P.S. Initially I created this polysurface in Rhino5 and later I opened and edited it with 6)