Preserve authored projection content and contextual canvas selection

crates/oa-core/src/validation.rs

@@ -620,11 +620,14 @@ pub fn validate(p: &Project) -> Vec<Issue> {
         text(&mut out, d.id, "name", &d.name);
         text(&mut out, d.id, "description", &d.description);
         crate::scenario_layout::validate_diagram(p, d, &mut out);
-        let option_issues = if d.projection == ProjectionKind::Traceability {
-            crate::view_options::validate_options_cross_layer(p, &d.view_options)
-        } else {
-            crate::view_options::validate_options(p, d.layer, &d.view_options)
-        };
+        // Ordinary projections are reversible filters over the same authored view.
+        // Retain opposite-layer visibility choices when leaving Traceability.
+        let option_issues =
+            if d.projection.state_machine().is_none() && d.projection.scenario().is_none() {
+                crate::view_options::validate_options_cross_layer(p, &d.view_options)
+            } else {
+                crate::view_options::validate_options(p, d.layer, &d.view_options)
+            };
         for issue in option_issues {
             error(&mut out, d.id, "view_options", issue.field, issue.message);
         }
@@ -798,8 +801,10 @@ pub fn validate(p: &Project) -> Vec<Issue> {
                 );
             }
             match p.elements.get(&n.element) {
-                Some(e) if d.projection == ProjectionKind::Traceability || e.layer() == d.layer => {
-                }
+                Some(e)
+                    if (d.projection.state_machine().is_none()
+                        && d.projection.scenario().is_none())
+                        || e.layer() == d.layer => {}
                 _ => error(
                     &mut out,
                     n.id,