Preserve scenario viewport when editing a diagram message

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

@@ -1221,8 +1221,11 @@ pub fn view<'a>(app: &'a App, owner: Id, mut out: Column<'a, Message>) -> Elemen
         }
     }));
     let pending = app.behavior.has_pending();
+    // Keep the canvas at a stable widget-tree position when a form replaces
+    // the palette, so Iced retains the user's current sequence viewport.
+    let mut controls = column![].spacing(12);
     if !pending {
-        out = out
+        controls = controls
             .push(
                 row![
                     action("+ Lifeline", event(Event::Start(owner, Tool::Lifeline))),
@@ -1252,7 +1255,7 @@ pub fn view<'a>(app: &'a App, owner: Id, mut out: Column<'a, Message>) -> Elemen
         MessageStyle::CallReply
     };
     if !pending {
-        out = out.push(
+        controls = controls.push(
             row![
                 button("Select / reorder")
                     .on_press(Message::ScenarioCanvas(CanvasEvent::Choose(
@@ -1296,14 +1299,15 @@ pub fn view<'a>(app: &'a App, owner: Id, mut out: Column<'a, Message>) -> Elemen
             ]
             .spacing(6),
         );
-        out = out.push(label(if matches!(tool, CanvasTool::Message(_)) {
+        controls = controls.push(label(if matches!(tool, CanvasTool::Message(_)) {
         "Draw message · choose the highlighted sequence position on a lifeline, then click or drag to another lifeline · Escape cancels"
     } else { "Select a lifeline or occurrence · drag the selected occurrence’s ↕ handle to reorder within its sequence" }));
     } else {
-        out = out.push(label(
+        controls = controls.push(label(
             "Pending form · the canvas remains visible · apply or cancel below",
         ));
     }
+    out = out.push(controls);
     let mut scene = Scene::sequence(p, owner, app.selected);
     scene.interaction = Some((
         context,

harness/STATE.md

@@ -204,12 +204,21 @@ logs desktop{-clippy,-release}-dfd2e41.log in Linux target/linux-verification.
 Semantic core/source5 checkpoint346fb24 passed345 core tests (one intentional
 ignored probe) and strict Clippy; independent nine-finding recheck is closed.
 Semantic checkout server test checkpointc746ab6 passes42 existing server tests
-and strict Clippy after seven current-output assertions changed to5. Semantic API
-production additions were rejected twice by automatic approval review; a direct
-authorization question is pending. No API route bodies were retained. Spec work
-continues independently. Process direct editing is active in codex/process-direct.
+and strict Clippy after seven current-output assertions changed to5. User explicitly reconfirmed REST work after two automatic review rejections.
+The scoped retry is approved; semantic query/preview/apply and HTTP tests are
+implemented, with independent transport review and schema validation active.
+Normative source5 spec02f99a9 passed strict generation and extracted examples;
+independent no-op-guarantee finding was fixed in29df024. Process direct editing is active in codex/process-direct.
 
 Next: verify scenario UI fixes on Windows/Linux; integrate semantic core/source,
 spec and authorized API; implement semantic GUI; integrate direct process editing.
 Broader coverage/lifecycle/hosted/help/release gates in PLAN remain active. Main
 is4101434 (docs pointer on productiona8f451e); this integration is not yet accepted.
+
+Latest native refinement c6c07cc: pinned actions/mode feedback/names pass normal
+and compact Windows inspection. Native ALT creation, operand pair insertion,
+correlation spans, invalid order, Save/Undo/Redo passed (saved62 objects). Canvas
+remount on entering/leaving forms loses the viewed region; stable controls sibling
+fix is being verified next. Exact evidence is in release-scenario-editing.md.
+Linux287 tests/strict Clippy/release passed c6c07cc. Process7a1e12b passes303 desktop
+tests; independent Exchange-first continuation finding is being fixed by worker.

harness/release-scenario-editing.md

@@ -256,3 +256,28 @@ inner and outer scrolling. Root is refining those three issues before accepting
 the milestone. ALT/reuse/resize/save recovery and Linux native remain pending.
 
 Root UI refinement checks:287 desktop tests passed, strict all-target desktop Clippy passed, optimized Windows desktop build passed. Native verification of this refinement remains pending.
+
+
+## Refined Windows native results and viewport finding
+
+c6c07cc Windows frozen binary SHA256
+4A49AD95C466BACBD1D1EA96FFF983BDA2F5DA9B7DCCBF91C387655CEF88B419,
+ui-scenario-refined-windows. Native1440x900 and1100x700 show differentiated tool
+selection, occurrence-first message names and pinned Create/Cancel. A pending
+Navigation outcome ALT fragment retained its name and route.available guard across
+width/height resizing. Create produced the fragment and two operands. Native
+click-click in its first operand explicitly captured that operand's append slot;
+Available route plus correlated Reply were created on Navigation request. Execution
+bar ends at that reply. Reply-before-call reorder rejects with reply_order. Save
+All writes62 objects/5 links/3 checks; exact nested source shows the guarded operand
+contains only that correlated pair. Undo removes both (60); Redo restores saved62.
+The saved native trial was closed before the next refinement.
+
+Native also found the canvas jumps to its start whenever the palette is replaced
+by a form or restored. Diagnosis: conditional siblings change its Iced widget-tree
+position. Group the controls as one stable sibling and verify that actual viewport
+is retained across drawing/form/cancel/create. This is distinct from deliberate
+new-selection reveal (not implemented yet). Linux287 tests, strict Clippy and
+optimized build pass for c6c07cc; native Linux remains pending.
+
+Stable-canvas refinement:287 desktop tests, strict all-target Clippy and optimized Windows build passed. Native retention trial remains pending.