Grow Scenario frames with preserved descendant padding

crates/oa-desktop/src/behavior/scenario_layout.rs

@@ -348,12 +348,14 @@ impl Plan {
                 if covered.y < rect.y {
                     return Err(GeometryIssue::FixedFrameHeaderWouldMove { frame: id });
                 }
-                if covered.y + covered.height > rect.y + rect.height {
+                let old_covered = old_coverage[&id];
-                    let old_covered = old_coverage[&id];
+                let padding =
-                    let padding =
+                    (original.y + original.height - old_covered.y - old_covered.height).max(0.);
-                        (original.y + original.height - old_covered.y - old_covered.height).max(0.);
+                // Preserve padding before the footprint itself reaches the old
-                    rect.height = covered.y + covered.height + padding - rect.y;
+                // frame edge: operand scopes already retain their own padding.
-                }
+                rect.height = rect
+                    .height
+                    .max(covered.y + covered.height + padding - rect.y);
             }
             frames.insert(id, rect);
             drawn.insert(id, rect);

crates/oa-desktop/src/behavior/scenario_layout/tests.rs

@@ -1050,6 +1050,19 @@ fn post_fragment_death_cannot_disappear_and_feasible_operand_spacing_retains_its
     let (document, owner, _, second, delete, right) = alternatives_with_death();
     let mut p = document.project().clone();
     let baseline = Scene::sequence(&p, owner, owner);
+    let operand = p.elements[&second].parent.unwrap();
+    let fragment = p.elements[&operand].parent.unwrap();
+    let baseline_frame = baseline
+        .boxes
+        .iter()
+        .find(|item| item.id == fragment)
+        .unwrap()
+        .rect;
+    assert_eq!(
+        (baseline_frame.y, baseline_frame.y + baseline_frame.height),
+        (148., 567.)
+    );
+    assert_eq!(baseline.sequence_bounds[&operand], (433., 525.));
     let x = baseline.render_lanes[&right];
     assert_eq!(baseline.rows[&delete].1, 631.);
     assert_eq!(
@@ -1064,6 +1077,23 @@ fn post_fragment_death_cannot_disappear_and_feasible_operand_spacing_retains_its
     );
     let view = saved(&mut p, owner, Some(positions(&[(second, 520.)], &[])));
     let resolved = result(&p, view);
+    // The message still lies above the old frame bottom, but its padded
+    // operand would end at 570. Retain the automatic 92px frame padding.
+    assert_eq!(resolved.scene.rows[&second].1, 520.);
+    assert_eq!(resolved.plan.scopes[&operand], (433., 570.));
+    let frame = resolved.plan.frames[&fragment];
+    assert_eq!((frame.y, frame.y + frame.height), (148., 612.));
+    assert_eq!(resolved.scene.sequence_bounds[&operand], (433., 570.));
+    assert_eq!(
+        resolved
+            .scene
+            .boxes
+            .iter()
+            .find(|item| item.id == fragment)
+            .unwrap()
+            .rect,
+        frame
+    );
     assert!(resolved.scene.lifecycle.missing_geometry().is_empty());
     assert_eq!(
         resolved.scene.lifecycle.marker_at(Point::new(x, 631.)),