Just encountered a recent phenomena. I must have hit the wrong button. I add a bezier curve and tab out of edti mode and the line disappears. Why does this happen? It hasn’t happened to me before.
Most likely you are in shaded view mode (z-key). Open curves will not be displayed shaded (there is nothing to shade).
To see a curve in shaded mode besides meshes, you have to set “wire” in the “Drawtype” menu in EditButtons for the curve.
I think you are right. Such a simple answer. Heh.