Preserve spline grip display mode after smooth solve

src/entities/spline.rs

@@ -128,7 +128,6 @@ pub(crate) fn replace_with_nurbs(spline: &mut Spline, curve: &NurbsCurve3) {
     spline.fit_points = fit_points;
     spline.begin_tangent = acadrust::types::Vector3::ZERO;
     spline.end_tangent = acadrust::types::Vector3::ZERO;
-    spline.cv_frame_visible = true;
     spline.flags.rational = spline.weights.windows(2)
         .any(|pair| (pair[0] - pair[1]).abs() > 1e-12);
     spline.flags.closed = false;

src/scene/parametric_solve.rs

@@ -2979,6 +2979,9 @@ fn solve_scope(
                     .collect();
                 if changed {
                     let mut updated = spline.clone();
+                    if crate::entities::spline::uses_fit_method(spline) {
+                        updated.cv_frame_visible = true;
+                    }
                     updated.degree = curve.degree as i32;
                     updated.knots = curve.knots.clone();
                     updated.control_points = control_points;