WIP: save unverified diagram Delete candidate at user pause

crates/oa-desktop/src/app.rs

@@ -3,6 +3,9 @@ pub(crate) mod architecture_authoring;
 #[cfg(test)]
 mod architecture_authoring_tests;
 mod checkpoints;
+pub(crate) mod diagram_removal;
+#[cfg(test)]
+mod diagram_removal_tests;
 #[cfg(test)]
 mod diagram_selection_tests;
 mod hosted;
@@ -393,7 +396,9 @@ pub enum Message {
     RelationKind(RelationKind),
     Command(Command),
     Delete,
-    ConfirmDelete,
+    ConfirmDelete(u64),
+    DiagramRemove(diagram_removal::Intent),
+    DiagramTraverse(bool),
     CancelDelete,
     Undo,
     Redo,
@@ -492,6 +497,7 @@ pub struct App {
     pub busy: bool,
     pub pending: Option<Pending>,
     pub delete_pending: bool,
+    pub delete_target: Option<diagram_removal::Confirmation>,
     pub path: Option<PathBuf>,
     /// A disk transaction requiring an explicit action, independent of lint.
     pub pending_recovery: Option<PathBuf>,
@@ -602,6 +608,7 @@ impl App {
             busy: false,
             pending: None,
             delete_pending: false,
+            delete_target: None,
             path: None,
             pending_recovery: None,
             disk_project: None,
@@ -1366,6 +1373,8 @@ impl App {
             }
             if self.delete_pending {
                 self.delete_pending = false;
+                self.delete_target = None;
+                self.canvas_epoch = self.canvas_epoch.wrapping_add(1);
                 return Task::none();
             }
             if self.pending.take().is_some() {
@@ -1400,7 +1409,7 @@ impl App {
                         Message::FilePath(_) | Message::SubmitFile | Message::CancelFile
                     ))
                 || (self.delete_pending
-                    && !matches!(message, Message::ConfirmDelete | Message::CancelDelete))
+                    && !matches!(message, Message::ConfirmDelete(_) | Message::CancelDelete))
                 || (self.pending.is_some()
                     && self.file_prompt.is_none()
                     && !matches!(
@@ -2778,19 +2787,25 @@ impl App {
                     }
                 }
             }
+            Message::DiagramRemove(intent) => self.remove_from_diagram(intent),
+            Message::DiagramTraverse(back) => {
+                return if back {
+                    iced::widget::operation::focus_previous()
+                } else {
+                    iced::widget::operation::focus_next()
+                };
+            }
             Message::Delete => {
                 if self.selected != self.project().id && self.apply() {
-                    self.delete_pending = true;
+                    self.begin_model_delete(None);
                 }
             }
-            Message::ConfirmDelete => {
-                if !self.delete_pending || self.behavior.has_pending() {
-                    return Task::none();
-                }
+            Message::ConfirmDelete(token) => self.confirm_model_delete(token),
+            Message::CancelDelete => {
                 self.delete_pending = false;
-                self.execute(Command::Delete(self.selected));
+                self.delete_target = None;
+                self.canvas_epoch = self.canvas_epoch.wrapping_add(1);
             }
-            Message::CancelDelete => self.delete_pending = false,
             Message::Undo | Message::Redo => {
                 let redo = matches!(message, Message::Redo);
                 if self.apply() {

crates/oa-desktop/src/app/behavior_lifecycle_tests.rs

@@ -291,7 +291,7 @@ fn pending_behavior_blocks_navigation_property_edits_and_model_history() {
         Message::BrowseGroup(crate::explorer::Group::Work),
         Message::Field("/name".into(), "Overwrite properties".into()),
         Message::Command(Command::Rename(fixture.source, "Overwrite model".into())),
-        Message::ConfirmDelete,
+        Message::ConfirmDelete(0),
         Message::Undo,
         Message::Redo,
         Message::ShortcutUndo(false),

crates/oa-desktop/src/app/diagram_removal.rs

@@ -0,0 +1,152 @@
+//! Captured diagram removal and model-confirmation lifetimes.
+use super::*;
+use crate::{model_menu, route_edit::Context};
+
+#[derive(Debug, Clone)]
+pub struct Intent {
+    pub context: Context,
+    pub object: Id,
+    pub placement: Option<Id>,
+    pub model: bool,
+}
+
+pub struct Confirmation {
+    pub snapshot: model_menu::Opened,
+    pub selection: Id,
+    pub placement: Option<Id>,
+}
+
+pub fn enabled(app: &App) -> bool {
+    crate::behavior::canvas_workspace::keyboard_enabled(app)
+        && !app.draft_dirty()
+        && !app.source_dirty()
+        && !app.behavior.has_pending()
+        && app
+            .architecture
+            .as_ref()
+            .is_none_or(|state| !state.inline())
+}
+
+impl App {
+    pub(super) fn remove_from_diagram(&mut self, intent: Intent) {
+        if !enabled(self) || self.connection.is_some() || self.selected_bend.is_some() {
+            return;
+        }
+        let current = match self.page {
+            Page::Diagram if self.architecture.as_ref().is_none_or(|s| !s.saved.placing) => {
+                self.route_context()
+            }
+            Page::Behavior
+                if self.behavior.diagram.tool == crate::behavior::state_edit::Tool::Select =>
+            {
+                self.state_context()
+            }
+            _ => None,
+        };
+        if current != Some(intent.context) || self.selected != intent.object {
+            return;
+        }
+        let view = projection::project_view(self.project(), intent.context.diagram);
+        let placement = if self.page == Page::Behavior {
+            self.behavior.diagram.placement
+        } else {
+            self.selected_node
+        };
+        if intent.placement != placement || intent.object == intent.context.diagram {
+            return;
+        }
+        let visible = if let Some(id) = intent.placement {
+            self.project().diagrams[&intent.context.diagram]
+                .nodes
+                .get(&id)
+                .is_some_and(|node| node.element == intent.object)
+                && view
+                    .nodes
+                    .iter()
+                    .any(|node| node.id == id && node.element == intent.object)
+        } else {
+            view.edges.iter().any(|edge| edge.id == intent.object)
+                || view.ports.iter().any(|port| port.element == intent.object)
+        };
+        if !visible {
+            return;
+        }
+        if !intent.model
+            && let Some(placement) = intent.placement
+        {
+            if self.execute(Command::Delete(placement)) {
+                self.selected_node = None;
+                self.behavior.diagram.placement = None;
+                self.selected_bend = None;
+                self.status = "Hidden from this diagram · Model element preserved · Undo restores the placement".into();
+            }
+        } else {
+            self.begin_model_delete(Some(intent.context));
+        }
+    }
+
+    pub(super) fn begin_model_delete(&mut self, canvas: Option<Context>) {
+        if self.selected == self.project().id || self.behavior.has_pending() {
+            return;
+        }
+        let mut request = model_menu::Request::object(self.selected, iced::Point::ORIGIN);
+        request.canvas = canvas;
+        request.placement = if self.page == Page::Behavior {
+            self.behavior.diagram.placement
+        } else {
+            self.selected_node
+        };
+        // Opening a modal retires any pending canvas intent before capturing
+        // the confirmation; every new dialog receives its own replay token.
+        self.canvas_epoch = self.canvas_epoch.wrapping_add(1);
+        if canvas.is_some() {
+            request.canvas = if self.page == Page::Behavior {
+                self.state_context()
+            } else {
+                self.route_context()
+            };
+        }
+        self.menu_sequence = self.menu_sequence.wrapping_add(1);
+        self.delete_target =
+            model_menu::Opened::new(self, request, self.menu_sequence).map(|snapshot| {
+                Confirmation {
+                    snapshot,
+                    selection: self.selected,
+                    placement: if self.page == Page::Behavior {
+                        self.behavior.diagram.placement
+                    } else {
+                        self.selected_node
+                    },
+                }
+            });
+        self.delete_pending = self.delete_target.is_some();
+    }
+
+    pub(super) fn confirm_model_delete(&mut self, token: u64) {
+        let Some(target) = self.delete_target.as_ref() else {
+            return;
+        };
+        if target.snapshot.token != token {
+            return;
+        }
+        let valid = self.delete_pending
+            && target.snapshot.valid(self)
+            && target.selection == self.selected
+            && target.placement
+                == if self.page == Page::Behavior {
+                    self.behavior.diagram.placement
+                } else {
+                    self.selected_node
+                }
+            && !self.behavior.has_pending()
+            && !self.source_dirty()
+            && !self.draft_dirty();
+        let id = target.snapshot.request.object;
+        self.delete_pending = false;
+        self.delete_target = None;
+        self.canvas_epoch = self.canvas_epoch.wrapping_add(1);
+        if valid {
+            self.execute(Command::Delete(id));
+        }
+    }
+}

crates/oa-desktop/src/app/diagram_removal_tests.rs

@@ -0,0 +1,681 @@
+//! Real App tree regression tests; no private canvas focus or gesture seeding.
+use super::*;
+use crate::behavior::canvas_workspace::tests::{Mounted, key};
+use iced::advanced::widget::{Operation, operation};
+use iced::{Event as Input, Point, Rectangle, Size, Vector, keyboard, mouse};
+
+struct Fixture {
+    app: App,
+    object: Id,
+    node: Id,
+    other: Id,
+    diagram: Id,
+    copy: Id,
+}
+fn fixture(layer: Layer) -> Fixture {
+    let mut p = Project::empty();
+    let kind = if layer == Layer::Oa {
+        Kind::Entity
+    } else {
+        Kind::System
+    };
+    let object = p.add_element(kind, layer, "Target", None).unwrap();
+    let other = p
+        .add_element(
+            if layer == Layer::Oa {
+                Kind::Actor
+            } else {
+                Kind::SystemActor
+            },
+            layer,
+            "Other",
+            None,
+        )
+        .unwrap();
+    let diagram = p.ensure_diagram(layer);
+    p.diagrams.get_mut(&diagram).unwrap().projection = ProjectionKind::Overview;
+    let node = p.place(diagram, object, Position { x: 80., y: 80. });
+    p.place(diagram, other, Position { x: 500., y: 80. });
+    let mut second = p.diagrams[&diagram].clone();
+    second.id = Id::new_v4();
+    second.name = "Other diagram".into();
+    second.alias = "other_diagram".into();
+    second.nodes.clear();
+    second.routes.clear();
+    let copy = second.id;
+    p.diagrams.insert(copy, second);
+    p.place(copy, object, Position { x: 70., y: 70. });
+    let mut app = App::with_project(p);
+    app.page = Page::Diagram;
+    app.layer = layer;
+    app.active_diagram = Some(diagram);
+    app.window_size = Size::new(2000., 1400.);
+    Fixture {
+        app,
+        object,
+        node,
+        other,
+        diagram,
+        copy,
+    }
+}
+async fn mount(layer: Layer) -> (Fixture, Mounted) {
+    let mut f = fixture(layer);
+    let mut mounted = Mounted::new(&mut f.app).await;
+    f.app.zoom = 1.;
+    f.app.pan = Vector::ZERO;
+    f.app.fit_to_view = false;
+    mounted.settle(&mut f.app).await;
+    select(&mut mounted, &mut f).await;
+    (f, mounted)
+}
+async fn select(mounted: &mut Mounted, f: &mut Fixture) {
+    let bounds = mounted
+        .geometry(&f.app)
+        .bounds(crate::allocation_input::CANVAS_ID);
+    let node = projection::project_view(f.app.project(), f.diagram)
+        .nodes
+        .into_iter()
+        .find(|node| node.id == f.node)
+        .unwrap();
+    let point = Point::new(
+        bounds.x + (node.position.x + 40.) * f.app.zoom + f.app.pan.x,
+        bounds.y + (node.position.y + 35.) * f.app.zoom + f.app.pan.y,
+    );
+    mounted.click(&mut f.app, point).await;
+    assert_eq!(f.app.selected, f.object);
+    assert_eq!(f.app.selected_node, Some(f.node));
+}
+fn modified(named: keyboard::key::Named, modifiers: keyboard::Modifiers) -> Input {
+    let mut input = key(named);
+    if let Input::Keyboard(keyboard::Event::KeyPressed {
+        modifiers: value, ..
+    }) = &mut input
+    {
+        *value = modifiers;
+    }
+    input
+}
+async fn delete(mounted: &mut Mounted, app: &mut App, shift: bool) -> Vec<Message> {
+    mounted
+        .batch(
+            app,
+            &[modified(
+                keyboard::key::Named::Delete,
+                if shift {
+                    keyboard::Modifiers::SHIFT
+                } else {
+                    keyboard::Modifiers::empty()
+                },
+            )],
+            mouse::Cursor::Unavailable,
+        )
+        .await
+}
+fn consistent(app: &App) {
+    assert_eq!(
+        source_project::compile_bundle(app.document.bundle(), LIMITS)
+            .unwrap()
+            .decoded
+            .project,
+        *app.project()
+    );
+    assert_eq!(
+        source_workspace::reachable(&app.source_workspace.bundle()).unwrap(),
+        *app.document.bundle()
+    );
+}
+
+#[tokio::test]
+async fn mounted_oa_sa_delete_hides_exact_placement_and_round_trips_source_and_model() {
+    for layer in [Layer::Oa, Layer::Sa] {
+        let (mut f, mut mounted) = mount(layer).await;
+        let before = f.app.document.snapshot();
+        let messages = delete(&mut mounted, &mut f.app, false).await;
+        assert!(
+            messages
+                .iter()
+                .any(|message| matches!(message, Message::DiagramRemove(_)))
+        );
+        assert!(f.app.project().contains(f.object));
+        assert!(
+            !f.app.project().diagrams[&f.diagram]
+                .nodes
+                .contains_key(&f.node)
+        );
+        assert!(
+            f.app.project().diagrams[&f.copy]
+                .nodes
+                .values()
+                .any(|node| node.element == f.object)
+        );
+        assert!(!f.app.delete_pending);
+        consistent(&f.app);
+        let after = f.app.document.snapshot();
+        let task = f.app.update(Message::Undo);
+        mounted.perform(&mut f.app, task).await;
+        assert_eq!(f.app.project(), &before.decoded.project);
+        assert_eq!(f.app.document.bundle(), &before.bundle);
+        assert!(!f.app.document.can_undo(), "one removal, one undo unit");
+        let task = f.app.update(Message::Redo);
+        mounted.perform(&mut f.app, task).await;
+        assert_eq!(f.app.project(), &after.decoded.project);
+        assert_eq!(f.app.document.bundle(), &after.bundle);
+        consistent(&f.app);
+    }
+}
+
+#[tokio::test]
+async fn mounted_shift_delete_captures_target_cancel_escape_and_confirmation_replay() {
+    let (mut f, mut mounted) = mount(Layer::Oa).await;
+    let before = f.app.document.snapshot();
+    delete(&mut mounted, &mut f.app, true).await;
+    let target = f.app.delete_target.as_ref().unwrap();
+    assert_eq!(target.snapshot.request.object, f.object);
+    let stale_token = target.snapshot.token;
+    let task = f.app.update(Message::CancelDelete);
+    mounted.perform(&mut f.app, task).await;
+    let task = f.app.update(Message::ConfirmDelete(stale_token));
+    mounted.perform(&mut f.app, task).await;
+    assert_eq!(f.app.document.bundle(), &before.bundle);
+    select(&mut mounted, &mut f).await;
+    delete(&mut mounted, &mut f.app, true).await;
+    let token = f.app.delete_target.as_ref().unwrap().snapshot.token;
+    let task = f.app.update(Message::ConfirmDelete(stale_token));
+    mounted.perform(&mut f.app, task).await;
+    assert!(
+        f.app.delete_pending,
+        "old dialog must not accept a new confirmation"
+    );
+    let task = f.app.update(Message::ConfirmDelete(token));
+    mounted.perform(&mut f.app, task).await;
+    assert!(!f.app.project().contains(f.object));
+    assert!(f.app.project().contains(f.other));
+    consistent(&f.app);
+    let task = f.app.update(Message::Undo);
+    mounted.perform(&mut f.app, task).await;
+    assert_eq!(f.app.document.bundle(), &before.bundle);
+    select(&mut mounted, &mut f).await;
+    delete(&mut mounted, &mut f.app, true).await;
+    let task = f.app.update(Message::Escape);
+    mounted.perform(&mut f.app, task).await;
+    assert!(!f.app.delete_pending);
+    assert!(f.app.delete_target.is_none());
+    assert_eq!(f.app.document.bundle(), &before.bundle);
+}
+
+struct FocusField(Rectangle);
+impl Operation for FocusField {
+    fn traverse(&mut self, visit: &mut dyn FnMut(&mut dyn Operation)) {
+        visit(self);
+    }
+    fn focusable(
+        &mut self,
+        _: Option<&iced::advanced::widget::Id>,
+        bounds: Rectangle,
+        state: &mut dyn operation::Focusable,
+    ) {
+        if bounds == self.0 {
+            state.focus();
+        } else {
+            state.unfocus();
+        }
+    }
+}
+fn name_field(mounted: &mut Mounted, app: &App) -> Rectangle {
+    mounted
+        .geometry(app)
+        .text_inputs
+        .into_iter()
+        .filter(|bounds| bounds.x > app.window_size.width - 320.)
+        .min_by(|a, b| a.y.total_cmp(&b.y))
+        .unwrap()
+}
+
+#[tokio::test]
+async fn mounted_clean_text_programmatic_focus_and_tab_remove_canvas_keyboard_ownership() {
+    for programmatic in [true, false] {
+        let (mut f, mut mounted) = mount(Layer::Oa).await;
+        let before = f.app.document.snapshot();
+        let field = name_field(&mut mounted, &f.app);
+        if programmatic {
+            mounted.operate(&f.app, &mut FocusField(field));
+        } else {
+            let messages = mounted
+                .batch(
+                    &mut f.app,
+                    &[
+                        key(keyboard::key::Named::Tab),
+                        key(keyboard::key::Named::Delete),
+                    ],
+                    mouse::Cursor::Unavailable,
+                )
+                .await;
+            assert!(
+                !messages
+                    .iter()
+                    .any(|message| matches!(message, Message::DiagramRemove(_))),
+                "Tab retires canvas admission before its queued focus operation runs"
+            );
+        }
+        let geometry = mounted.geometry(&f.app);
+        assert!(
+            geometry
+                .focused
+                .iter()
+                .any(|(_, bounds, focused)| *bounds == field && *focused),
+            "clean Inspector receives real focus"
+        );
+        assert!(!f.app.draft_dirty());
+        assert!(
+            delete(&mut mounted, &mut f.app, true)
+                .await
+                .iter()
+                .all(|message| !matches!(message, Message::DiagramRemove(_)))
+        );
+        assert!(!f.app.delete_pending);
+        mounted
+            .batch(
+                &mut f.app,
+                &[key(keyboard::key::Named::Home)],
+                mouse::Cursor::Unavailable,
+            )
+            .await;
+        let messages = delete(&mut mounted, &mut f.app, false).await;
+        assert!(
+            messages
+                .iter()
+                .any(|message| matches!(message, Message::Field(path, _) if path == "/name"))
+        );
+        assert_eq!(f.app.draft.as_ref().unwrap().inputs["/name"].raw, "arget");
+        assert_eq!(f.app.document.bundle(), &before.bundle);
+        assert!(f.app.project().contains(f.node));
+        assert!(!f.app.delete_pending);
+    }
+}
+
+#[tokio::test]
+async fn mounted_removal_intents_reject_stale_selection_revision_owner_and_document() {
+    for boundary in 0..5 {
+        let (mut f, mut mounted) = mount(Layer::Oa).await;
+        let messages = mounted.input(
+            &f.app,
+            &[key(keyboard::key::Named::Delete)],
+            mouse::Cursor::Unavailable,
+        );
+        let intent = messages
+            .into_iter()
+            .find(|message| matches!(message, Message::DiagramRemove(_)))
+            .unwrap();
+        match boundary {
+            0 => {
+                let _ = f.app.update(Message::Select(f.other));
+            }
+            1 => {
+                f.app.canvas_epoch = f.app.canvas_epoch.wrapping_add(1);
+            }
+            2 => {
+                f.app.active_diagram = Some(f.copy);
+            }
+            3 => {
+                f.app.canvas_document = Id::new_v4();
+            }
+            _ => {
+                let _ = f
+                    .app
+                    .update(Message::Command(Command::Rename(f.other, "Renamed".into())));
+            }
+        }
+        let before = f.app.document.snapshot();
+        let task = f.app.update(intent);
+        mounted.perform(&mut f.app, task).await;
+        assert_eq!(f.app.document.bundle(), &before.bundle);
+        assert!(f.app.project().contains(f.node));
+        assert!(!f.app.delete_pending);
+    }
+}
+
+#[tokio::test]
+async fn mounted_window_modal_dirty_and_modifier_boundaries_retire_delete_focus() {
+    for boundary in 0..5 {
+        let (mut f, mut mounted) = mount(Layer::Oa).await;
+        let before = f.app.document.snapshot();
+        match boundary {
+            0 => {
+                mounted
+                    .batch(
+                        &mut f.app,
+                        &[Input::Window(iced::window::Event::Unfocused)],
+                        mouse::Cursor::Unavailable,
+                    )
+                    .await;
+            }
+            1 => {
+                let _ = f.app.update(Message::Menu(crate::model_menu::Event::Open(
+                    crate::model_menu::Request::object(f.object, Point::ORIGIN),
+                )));
+                mounted.settle(&mut f.app).await;
+                let _ = f.app.update(Message::Menu(crate::model_menu::Event::Close));
+            }
+            2 => {
+                let _ = f.app.update(Message::Field("/name".into(), "Dirty".into()));
+            }
+            3 => {
+                let _ = f.app.update(Message::Delete);
+            }
+            _ => {
+                f.app.canvas_epoch = f.app.canvas_epoch.wrapping_add(1);
+            }
+        }
+        delete(&mut mounted, &mut f.app, false).await;
+        assert_eq!(f.app.document.bundle(), &before.bundle);
+        assert!(f.app.project().contains(f.node));
+    }
+    let (mut f, mut mounted) = mount(Layer::Oa).await;
+    let before = f.app.document.snapshot();
+    mounted
+        .batch(
+            &mut f.app,
+            &[modified(
+                keyboard::key::Named::Delete,
+                keyboard::Modifiers::CTRL,
+            )],
+            mouse::Cursor::Unavailable,
+        )
+        .await;
+    assert_eq!(f.app.document.bundle(), &before.bundle);
+    assert!(!f.app.delete_pending);
+    // Refusal is temporary: a fresh live canvas click owns Delete again.
+    select(&mut mounted, &mut f).await;
+    delete(&mut mounted, &mut f.app, false).await;
+    assert!(!f.app.project().contains(f.node));
+}
+
+#[tokio::test]
+async fn mounted_bend_delete_has_priority_and_semantic_edge_delete_is_confirmed() {
+    let mut p = Project::empty();
+    let a = p.add(Kind::Activity, "Send", 0., 0.);
+    let b = p.add(Kind::Activity, "Receive", 650., 0.);
+    let edge = p.relate(RelationKind::Interaction, "Report", a, b);
+    let diagram = p.ensure_diagram(Layer::Oa);
+    let p = execute_batch(
+        &p,
+        &[Command::SetEdgeRoute {
+            diagram,
+            route: EdgeRoute {
+                edge,
+                waypoints: vec![Position { x: 400., y: -100. }],
+                label: None,
+            },
+        }],
+    )
+    .unwrap();
+    let mut app = App::with_project(p);
+    app.page = Page::Diagram;
+    app.active_diagram = Some(diagram);
+    app.window_size = Size::new(2000., 1400.);
+    let _ = app.update(Message::Select(edge));
+    let mut mounted = Mounted::new(&mut app).await;
+    app.zoom = 1.;
+    app.pan = Vector::new(100., 250.);
+    app.fit_to_view = false;
+    mounted.settle(&mut app).await;
+    let bounds = mounted
+        .geometry(&app)
+        .bounds(crate::allocation_input::CANVAS_ID);
+    let pin = Point::new(bounds.x + 500., bounds.y + 150.);
+    mounted.click(&mut app, pin).await;
+    assert_eq!(
+        app.selected_bend,
+        Some((edge, 0)),
+        "real pointer selects route pin"
+    );
+    let before = app.document.snapshot();
+    let messages = delete(&mut mounted, &mut app, false).await;
+    assert!(messages.iter().any(|message| matches!(
+        message,
+        Message::Route(crate::route_edit::Event::RemoveBend)
+    )));
+    assert!(
+        !messages
+            .iter()
+            .any(|message| matches!(message, Message::DiagramRemove(_)))
+    );
+    assert!(app.project().contains(edge) && app.project().contains(a) && app.project().contains(b));
+    assert!(
+        crate::route_edit::stored_route(&app.project().diagrams[&diagram], edge)
+            .waypoints
+            .is_empty()
+    );
+    assert!(!app.delete_pending);
+    consistent(&app);
+    let task = app.update(Message::Undo);
+    mounted.perform(&mut app, task).await;
+    assert_eq!(app.document.bundle(), &before.bundle);
+    // Select a real edge segment away from its handle, then Delete opens the
+    // same semantic confirmation instead of inventing an edge hide operation.
+    let view = projection::project_view(app.project(), diagram);
+    let routed = routing::route_diagram(app.project(), &app.project().diagrams[&diagram], &view);
+    let route = &routed.edges[&edge];
+    let segment = route
+        .points
+        .windows(2)
+        .max_by(|a, b| {
+            let len = |s: &[Position]| (s[1].x - s[0].x).abs() + (s[1].y - s[0].y).abs();
+            len(a).total_cmp(&len(b))
+        })
+        .unwrap();
+    let at = Point::new(
+        bounds.x + (segment[0].x + segment[1].x) / 2. + app.pan.x,
+        bounds.y + (segment[0].y + segment[1].y) / 2. + app.pan.y,
+    );
+    mounted.click(&mut app, at).await;
+    assert_eq!(app.selected, edge);
+    assert!(app.selected_bend.is_none());
+    delete(&mut mounted, &mut app, false).await;
+    assert_eq!(
+        app.delete_target.as_ref().unwrap().snapshot.request.object,
+        edge
+    );
+    assert_eq!(app.document.bundle(), &before.bundle);
+}
+
+#[tokio::test]
+async fn mounted_state_delete_uses_state_placement_and_preserves_architecture_placement() {
+    let mut p = Project::empty();
+    let machine = p
+        .add_element(Kind::StateMachine, Layer::Sa, "Machine", None)
+        .unwrap();
+    let region = p
+        .add_element(Kind::Region, Layer::Sa, "Main", Some(machine))
+        .unwrap();
+    let state = p
+        .add_element(Kind::State, Layer::Sa, "Ready", Some(region))
+        .unwrap();
+    let architecture = p.ensure_diagram(Layer::Sa);
+    let architecture_node = p.place(architecture, state, Position { x: 50., y: 50. });
+    let plan = crate::behavior::state_edit::create_view(&p, machine).unwrap();
+    let diagram = plan.diagram;
+    let p = execute_batch(&p, &[plan.command]).unwrap();
+    let node = p.diagrams[&diagram]
+        .nodes
+        .values()
+        .find(|node| node.element == state)
+        .unwrap()
+        .id;
+    let mut app = App::with_project(p);
+    app.layer = Layer::Sa;
+    app.page = Page::Behavior;
+    app.active_diagram = Some(architecture);
+    app.behavior.active_owner = Some(machine);
+    app.behavior.diagram.diagram = Some(diagram);
+    app.window_size = Size::new(2000., 1400.);
+    let _ = app.update(Message::Select(state));
+    let mut mounted = Mounted::new(&mut app).await;
+    let bounds = mounted
+        .geometry(&app)
+        .focused
+        .into_iter()
+        .find(|(id, _, _)| {
+            id.as_ref() == Some(&iced::advanced::widget::Id::from("diagram-keyboard-owner"))
+        })
+        .unwrap()
+        .1;
+    let projected = projection::project_view(app.project(), diagram)
+        .nodes
+        .into_iter()
+        .find(|n| n.id == node)
+        .unwrap();
+    let at = Point::new(
+        bounds.x
+            + (projected.position.x + 35.) * app.behavior.diagram.zoom
+            + app.behavior.diagram.pan.x,
+        bounds.y
+            + (projected.position.y + 35.) * app.behavior.diagram.zoom
+            + app.behavior.diagram.pan.y,
+    );
+    mounted.click(&mut app, at).await;
+    assert_eq!(app.selected, state);
+    assert_eq!(app.behavior.diagram.placement, Some(node));
+    let before = app.document.snapshot();
+    let messages = delete(&mut mounted, &mut app, false).await;
+    assert!(messages.iter().any(|message| matches!(
+        message,
+        Message::StateDiagram(crate::behavior::state_edit::Event::Remove(_))
+    )));
+    assert!(!app.project().contains(node));
+    assert!(app.project().contains(architecture_node) && app.project().contains(state));
+    consistent(&app);
+    let task = app.update(Message::Undo);
+    mounted.perform(&mut app, task).await;
+    assert_eq!(app.document.bundle(), &before.bundle);
+}
+
+#[tokio::test]
+async fn captured_confirmation_rejects_selection_document_revision_and_placement_changes() {
+    for boundary in 0..5 {
+        let (mut f, mut mounted) = mount(Layer::Oa).await;
+        delete(&mut mounted, &mut f.app, true).await;
+        let token = f.app.delete_target.as_ref().unwrap().snapshot.token;
+        // Model asynchronous adoption / retained stale UI using a changed App
+        // state while preserving the old confirmation payload deliberately.
+        match boundary {
+            0 => {
+                f.app.selected = f.other;
+            }
+            1 => {
+                f.app.canvas_document = Id::new_v4();
+            }
+            2 => {
+                f.app.canvas_epoch = f.app.canvas_epoch.wrapping_add(1);
+            }
+            3 => {
+                f.app.selected_node = None;
+            }
+            _ => {
+                assert!(
+                    f.app
+                        .document
+                        .execute(Command::Rename(f.other, "New revision".into()))
+                        .is_ok()
+                );
+            }
+        }
+        let before = f.app.document.snapshot();
+        let task = f.app.update(Message::ConfirmDelete(token));
+        mounted.perform(&mut f.app, task).await;
+        assert_eq!(f.app.document.bundle(), &before.bundle);
+        assert!(f.app.project().contains(f.object));
+        assert!(!f.app.delete_pending);
+    }
+}
+
+#[tokio::test]
+async fn mounted_programmatic_canvas_entry_needs_no_mouse_focus_boolean() {
+    let mut f = fixture(Layer::Oa);
+    let _ = f.app.update(Message::Select(f.object));
+    let mut mounted = Mounted::new(&mut f.app).await;
+    let task =
+        iced::widget::operation::focus(iced::advanced::widget::Id::from("diagram-keyboard-owner"));
+    mounted.perform(&mut f.app, task).await;
+    let messages = delete(&mut mounted, &mut f.app, false).await;
+    assert!(
+        messages
+            .iter()
+            .any(|message| matches!(message, Message::DiagramRemove(_)))
+    );
+    assert!(!f.app.project().contains(f.node));
+    assert!(f.app.project().contains(f.object));
+}
+
+#[tokio::test]
+async fn mounted_allocation_work_click_then_delete_without_redraw_removes_placement_once() {
+    for layer in [Layer::Oa, Layer::Sa] {
+        let mut p = Project::empty();
+        let performer = p
+            .add_element(
+                if layer == Layer::Oa {
+                    Kind::Entity
+                } else {
+                    Kind::System
+                },
+                layer,
+                "Performer",
+                None,
+            )
+            .unwrap();
+        let work = p
+            .add_element(
+                if layer == Layer::Oa {
+                    Kind::Activity
+                } else {
+                    Kind::Function
+                },
+                layer,
+                "Work",
+                None,
+            )
+            .unwrap();
+        let diagram = p.ensure_diagram(layer);
+        p.diagrams.get_mut(&diagram).unwrap().projection = ProjectionKind::Allocation;
+        p.place(diagram, performer, Position { x: 100., y: 100. });
+        let node = p.place(diagram, work, Position { x: 100., y: 500. });
+        let mut app = App::with_project(p);
+        app.page = Page::Diagram;
+        app.layer = layer;
+        app.active_diagram = Some(diagram);
+        app.window_size = Size::new(2000., 1400.);
+        let mut mounted = Mounted::new(&mut app).await;
+        app.zoom = 1.;
+        app.pan = Vector::ZERO;
+        app.fit_to_view = false;
+        mounted.settle(&mut app).await;
+        let bounds = mounted
+            .geometry(&app)
+            .bounds(crate::allocation_input::CANVAS_ID);
+        let point = Point::new(bounds.x + 140., bounds.y + 535.);
+        let messages = mounted.click(&mut app, point).await;
+        assert!(messages.iter().any(|message| matches!(
+            message,
+            Message::WorkDrag(crate::app::allocation_drag::Event::Press(_))
+        )));
+        assert_eq!(app.selected, work);
+        assert_eq!(app.selected_node, Some(node));
+        let before = app.document.snapshot();
+        // Deliberately do not settle/redraw between completed click and key.
+        let messages = delete(&mut mounted, &mut app, false).await;
+        assert!(
+            messages
+                .iter()
+                .any(|message| matches!(message, Message::DiagramRemove(_))),
+            "retired allocation press cannot consume first Delete"
+        );
+        assert!(!app.project().contains(node));
+        assert!(app.project().contains(work) && app.project().contains(performer));
+        consistent(&app);
+        let task = app.update(Message::Undo);
+        mounted.perform(&mut app, task).await;
+        assert_eq!(app.document.bundle(), &before.bundle);
+        assert!(!app.document.can_undo());
+    }
+}

crates/oa-desktop/src/app/state_diagram.rs

@@ -114,6 +114,7 @@ impl App {
             }
         }
         match event {
+            Event::Remove(intent) => self.remove_from_diagram(intent),
             Event::Viewport(_, size) => {
                 if size.width.is_finite()
                     && size.height.is_finite()

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

@@ -38,7 +38,6 @@ pub struct State {
     context: Option<Context>,
     tool: Option<Tool>,
     pointer: Option<Point>,
-    focused: bool,
     press: Option<Press>,
     source: Option<Id>,
     preview: Option<(Id, Position)>,
@@ -771,7 +770,6 @@ impl canvas::Program<Event> for StateCanvas<'_> {
             }
             canvas::Event::Window(iced::window::Event::Unfocused) => {
                 state.reset();
-                state.focused = false;
                 return None;
             }
             _ => cursor,
@@ -779,14 +777,40 @@ impl canvas::Program<Event> for StateCanvas<'_> {
         let window = cursor.position();
         let local = window.map(|p| Point::new(p.x - bounds.x, p.y - bounds.y));
         let inside = local.is_some_and(|p| Self::content(bounds).contains(p));
-        if let canvas::Event::Keyboard(keyboard::Event::KeyPressed { key, modifiers, .. }) = event
-            && state.focused
-        {
+        if let canvas::Event::Keyboard(keyboard::Event::KeyPressed { key, modifiers, .. }) = event {
             use keyboard::{Key, key::Named};
             if *key == Key::Named(Named::Escape) {
                 state.reset();
                 return Some(Action::publish(Event::Choose(Tool::Select)).and_capture());
             }
+            if *key == Key::Named(Named::Delete)
+                && self.editable
+                && self.tool == Tool::Select
+                && state.press.is_none()
+                && state.pan_from.is_none()
+                && state.source.is_none()
+                && (modifiers.is_empty() || *modifiers == keyboard::Modifiers::SHIFT)
+            {
+                let scene = self.scene(state)?;
+                let placement = scene
+                    .view
+                    .nodes
+                    .iter()
+                    .find(|node| node.element == self.selected || node.id == self.selected);
+                let object = placement.map_or(self.selected, |node| node.element);
+                if placement.is_none() && !scene.view.edges.iter().any(|edge| edge.id == object) {
+                    return None;
+                }
+                return Some(
+                    Action::publish(Event::Remove(crate::app::diagram_removal::Intent {
+                        context: self.context,
+                        object,
+                        placement: placement.map(|node| node.id),
+                        model: modifiers.shift(),
+                    }))
+                    .and_capture(),
+                );
+            }
             if modifiers.is_empty() {
                 let pan = match key.as_ref() {
                     Key::Named(Named::ArrowLeft) => Some(Vector::new(60., 0.)),
@@ -804,7 +828,6 @@ impl canvas::Program<Event> for StateCanvas<'_> {
         let scene = self.scene(state)?;
         match event {
             canvas::Event::Mouse(mouse::Event::ButtonPressed(button)) => {
-                state.focused = inside;
                 if !inside {
                     return None;
                 }

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

@@ -24,6 +24,7 @@ pub enum Tool {
 
 #[derive(Debug, Clone)]
 pub enum Event {
+    Remove(crate::app::diagram_removal::Intent),
     Choose(Tool),
     CreateView(Id),
     Select(Context, Id),
@@ -70,6 +71,7 @@ pub enum Event {
 impl Event {
     pub fn context(&self) -> Option<Context> {
         match self {
+            Self::Remove(intent) => Some(intent.context),
             Self::Choose(_) | Self::CreateView(_) => None,
             Self::Select(c, _)
             | Self::Pan(c, _)

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

@@ -139,11 +139,14 @@ pub fn popup(app: &App, opened: &Opened, clean: bool) -> Option<Menu<Message>> {
                         true,
                     ));
                 }
-                entries.push(item(
-                    "Hide from this diagram",
-                    Message::Command(Command::Delete(node.id)),
-                    true,
-                ));
+                entries.push(
+                    item(
+                        "Hide from this diagram",
+                        Message::Command(Command::Delete(node.id)),
+                        true,
+                    )
+                    .shortcut("Delete"),
+                );
             }
         }
         if let Some(relation) = project.relations.get(&id)
@@ -184,7 +187,24 @@ pub fn popup(app: &App, opened: &Opened, clean: bool) -> Option<Menu<Message>> {
         }
         if id != project.id {
             entries.push(Entry::separator());
-            entries.push(item("Delete from model…", Message::Delete, true));
+            entries.push(item("Delete from model…", Message::Delete, true).shortcut(
+                if context.is_some_and(|context| {
+                    context.diagram != id
+                        && (request.placement.is_some()
+                            || projection::project_view(project, context.diagram)
+                                .edges
+                                .iter()
+                                .any(|edge| edge.id == id))
+                }) {
+                    if request.placement.is_some() {
+                        "Shift+Delete"
+                    } else {
+                        "Delete / Shift+Delete"
+                    }
+                } else {
+                    ""
+                },
+            ));
         }
     }
     Some(Menu {

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

@@ -173,7 +173,12 @@ pub fn view<'a>(app: &'a App, machine: Id, mut out: Column<'a, Message>) -> Elem
     .width(Fill)
     .height(Fill)
     .into();
-    out = out.push(canvas.map(event));
+    out = out.push(crate::diagram::focus::wrap(
+        canvas.map(event),
+        context,
+        crate::app::diagram_removal::enabled(app),
+        Message::DiagramTraverse,
+    ));
     let base: Element<'_, Message> = container(out.spacing(8))
         .padding(14)
         .width(Fill)

crates/oa-desktop/src/diagram.rs

@@ -34,6 +34,8 @@ mod view_options_tests;
 #[path = "diagram/port_labels.rs"]
 mod port_labels;
 pub use port_labels::PortLabels;
+#[path = "diagram/focus.rs"]
+pub(crate) mod focus;
 #[path = "diagram/work_drag.rs"]
 mod work_drag;
 pub use work_drag::WorkFeedback;
@@ -58,7 +60,6 @@ pub struct State {
     work: Option<Arc<crate::app::allocation_drag::Press>>,
     work_cache: RefCell<Option<Arc<Scene>>>,
     pointer: Option<Point>,
-    keyboard_focus: bool,
     drag: Option<(Id, Point, Position)>,
     preview: Option<Position>,
     pan_start: Option<(mouse::Button, Point)>,
@@ -558,6 +559,21 @@ impl canvas::Program<Message> for DiagramCanvas<'_> {
         bounds: Rectangle,
         cursor: mouse::Cursor,
     ) -> Option<Action<Message>> {
+        // A completed work click retires App's allocation epoch before the
+        // retained canvas sees a redraw. Its already-idle press must not eat
+        // the first Delete. A live or not-yet-dispatched press stays guarded.
+        if matches!(event, canvas::Event::Keyboard(iced::keyboard::Event::KeyPressed { key, .. })
+            if *key == iced::keyboard::Key::Named(iced::keyboard::key::Named::Delete))
+            && self.allocation.is_some_and(|capability| {
+                capability.clean
+                    && state
+                        .work
+                        .as_ref()
+                        .is_some_and(|press| press.stamp.epoch != capability.state.epoch)
+            })
+        {
+            state.work = None;
+        }
         if let Some(action) = self.work_lifetime(state, event, bounds) {
             return Some(action);
         }
@@ -628,9 +644,6 @@ impl canvas::Program<Message> for DiagramCanvas<'_> {
         let local = cursor
             .position()
             .map(|p| Point::new(p.x - bounds.x, p.y - bounds.y));
-        if matches!(event, canvas::Event::Mouse(mouse::Event::ButtonPressed(_))) {
-            state.keyboard_focus = cursor.is_over(bounds);
-        }
         match event {
             canvas::Event::Mouse(mouse::Event::ButtonPressed(mouse::Button::Right))
                 if cursor.is_over(bounds) =>
@@ -650,7 +663,8 @@ impl canvas::Program<Message> for DiagramCanvas<'_> {
             }
             canvas::Event::Keyboard(iced::keyboard::Event::KeyPressed {
                 key, modifiers, ..
-            }) if state.keyboard_focus => {
+            }) => {
+                // The mounted focus::Owner is the sole keyboard admission gate.
                 use iced::keyboard::{Key, key::Named};
                 match key.as_ref() {
                     Key::Named(Named::F2)
@@ -705,10 +719,37 @@ impl canvas::Program<Message> for DiagramCanvas<'_> {
                     Key::Named(Named::Delete)
                         if self.editable
                             && self.connection.is_none()
-                            && modifiers.is_empty()
-                            && self.selected_bend.is_some() =>
+                            && !self.placing
+                            && state.drag.is_none()
+                            && state.route_drag.is_none()
+                            && state.port_drag.is_none()
+                            && state.pan_start.is_none()
+                            && state.work.is_none()
+                            && (modifiers.is_empty()
+                                || *modifiers == iced::keyboard::Modifiers::SHIFT) =>
                     {
-                        Some(Action::publish(Message::Route(RouteEvent::RemoveBend)).and_capture())
+                        // An invalid/stale bend never falls through to whole-item removal.
+                        if self.selected_bend.is_some() {
+                            return modifiers.is_empty().then(|| {
+                                Action::publish(Message::Route(RouteEvent::RemoveBend))
+                                    .and_capture()
+                            });
+                        }
+                        let request = self.selection_context_request(state, bounds);
+                        if request.object == self.diagram {
+                            return None;
+                        }
+                        Some(
+                            Action::publish(Message::DiagramRemove(
+                                crate::app::diagram_removal::Intent {
+                                    context: self.context,
+                                    object: request.object,
+                                    placement: request.placement,
+                                    model: modifiers.shift(),
+                                },
+                            ))
+                            .and_capture(),
+                        )
                     }
                     _ => None,
                 }

crates/oa-desktop/src/diagram/focus.rs

@@ -0,0 +1,244 @@
+//! Iced focus ownership shared by architecture and persisted state canvases.
+//! Focus operations (including clean Inspector focus) unfocus this widget.
+use crate::route_edit::Context;
+use iced::advanced::widget::{Operation, Tree, operation};
+use iced::advanced::{Clipboard, Layout, Shell, Widget, layout, overlay, renderer};
+use iced::{Element, Event as InputEvent, Length, Point, Rectangle, Size, Theme, Vector, mouse};
+#[derive(Default)]
+struct Input {
+    context: Option<Context>,
+    focused: bool,
+    traversing: bool,
+    pointer: Option<Point>,
+}
+impl operation::Focusable for Input {
+    fn is_focused(&self) -> bool {
+        self.focused
+    }
+    fn focus(&mut self) {
+        self.focused = true;
+        self.traversing = false;
+    }
+    fn unfocus(&mut self) {
+        self.focused = false;
+        self.traversing = false;
+    }
+}
+struct Owner<'a, Message, R: renderer::Renderer> {
+    context: Context,
+    enabled: bool,
+    traverse: Box<dyn Fn(bool) -> Message + 'a>,
+    content: Element<'a, Message, Theme, R>,
+}
+pub fn wrap<'a, Message: 'a, R: renderer::Renderer + 'a>(
+    content: impl Into<Element<'a, Message, Theme, R>>,
+    context: Context,
+    enabled: bool,
+    traverse: impl Fn(bool) -> Message + 'a,
+) -> Element<'a, Message, Theme, R> {
+    Element::new(Owner {
+        context,
+        enabled,
+        traverse: Box::new(traverse),
+        content: content.into(),
+    })
+}
+impl<Message, R: renderer::Renderer> Widget<Message, Theme, R> for Owner<'_, Message, R> {
+    fn tag(&self) -> iced::advanced::widget::tree::Tag {
+        iced::advanced::widget::tree::Tag::of::<Input>()
+    }
+    fn state(&self) -> iced::advanced::widget::tree::State {
+        iced::advanced::widget::tree::State::new(Input {
+            context: Some(self.context),
+            ..Default::default()
+        })
+    }
+    fn children(&self) -> Vec<Tree> {
+        vec![Tree::new(self.content.as_widget())]
+    }
+
+    fn diff(&self, tree: &mut Tree) {
+        let state = tree.state.downcast_mut::<Input>();
+        if state.context != Some(self.context) || !self.enabled {
+            state.focused = false;
+            state.traversing = false;
+            state.pointer = None;
+        }
+        state.context = Some(self.context);
+        tree.diff_children(std::slice::from_ref(&self.content));
+    }
+
+    fn size(&self) -> Size<Length> {
+        self.content.as_widget().size()
+    }
+
+    fn layout(&mut self, tree: &mut Tree, renderer: &R, limits: &layout::Limits) -> layout::Node {
+        self.content
+            .as_widget_mut()
+            .layout(&mut tree.children[0], renderer, limits)
+    }
+
+    fn operate(
+        &mut self,
+        tree: &mut Tree,
+        layout: Layout<'_>,
+        renderer: &R,
+        operation: &mut dyn Operation,
+    ) {
+        if self.enabled {
+            operation.focusable(
+                Some(&iced::advanced::widget::Id::from("diagram-keyboard-owner")),
+                layout.bounds(),
+                tree.state.downcast_mut::<Input>(),
+            );
+        }
+        self.content
+            .as_widget_mut()
+            .operate(&mut tree.children[0], layout, renderer, operation);
+    }
+
+    fn update(
+        &mut self,
+        tree: &mut Tree,
+        event: &InputEvent,
+        layout: Layout<'_>,
+        cursor: mouse::Cursor,
+        renderer: &R,
+        clipboard: &mut dyn Clipboard,
+        shell: &mut Shell<'_, Message>,
+        viewport: &Rectangle,
+    ) {
+        let state = tree.state.downcast_mut::<Input>();
+        if let InputEvent::Mouse(mouse::Event::CursorMoved { position }) = event {
+            state.pointer = Some(*position);
+        }
+        if matches!(
+            event,
+            InputEvent::Window(iced::window::Event::Unfocused | iced::window::Event::Resized(_))
+        ) || !self.enabled
+        {
+            state.focused = false;
+            state.traversing = false;
+            state.pointer = None;
+        }
+        if matches!(event, InputEvent::Mouse(mouse::Event::ButtonPressed(_))) {
+            state.traversing = false;
+            let pointer = state.pointer.or_else(|| cursor.position());
+            state.focused = self.enabled
+                && !shell.is_event_captured()
+                && cursor.position().is_some()
+                && pointer.is_some_and(|p| {
+                    layout
+                        .bounds()
+                        .intersection(viewport)
+                        .is_some_and(|b| b.contains(p))
+                });
+        }
+        if let InputEvent::Keyboard(iced::keyboard::Event::KeyPressed {
+            key: iced::keyboard::Key::Named(iced::keyboard::key::Named::Tab),
+            modifiers,
+            ..
+        }) = event
+            && state.focused
+            && !state.traversing
+            && self.enabled
+            && !shell.is_event_captured()
+            && (*modifiers == iced::keyboard::Modifiers::SHIFT || modifiers.is_empty())
+        {
+            // The focus task runs after the native batch. Retain focus for its
+            // traversal count, but reject later keys in this same batch now.
+            state.traversing = true;
+            shell.publish((self.traverse)(modifiers.shift()));
+            shell.capture_event();
+            return;
+        }
+        if matches!(event, InputEvent::Keyboard(_))
+            && (!state.focused || state.traversing || !self.enabled)
+        {
+            return;
+        }
+        if shell.is_event_captured() {
+            return;
+        }
+        self.content.as_widget_mut().update(
+            &mut tree.children[0],
+            event,
+            layout,
+            cursor,
+            renderer,
+            clipboard,
+            shell,
+            viewport,
+        );
+    }
+
+    fn draw(
+        &self,
+        tree: &Tree,
+        renderer: &mut R,
+        theme: &Theme,
+        style: &renderer::Style,
+        layout: Layout<'_>,
+        cursor: mouse::Cursor,
+        viewport: &Rectangle,
+    ) {
+        self.content.as_widget().draw(
+            &tree.children[0],
+            renderer,
+            theme,
+            style,
+            layout,
+            cursor,
+            viewport,
+        );
+        let state = tree.state.downcast_ref::<Input>();
+        if state.focused && !state.traversing && self.enabled {
+            renderer.fill_quad(
+                renderer::Quad {
+                    bounds: layout.bounds(),
+                    border: iced::Border {
+                        color: crate::style::TEAL,
+                        width: 1.,
+                        ..Default::default()
+                    },
+                    ..Default::default()
+                },
+                iced::Color::TRANSPARENT,
+            );
+        }
+    }
+
+    fn mouse_interaction(
+        &self,
+        tree: &Tree,
+        layout: Layout<'_>,
+        cursor: mouse::Cursor,
+        viewport: &Rectangle,
+        renderer: &R,
+    ) -> mouse::Interaction {
+        self.content.as_widget().mouse_interaction(
+            &tree.children[0],
+            layout,
+            cursor,
+            viewport,
+            renderer,
+        )
+    }
+
+    fn overlay<'b>(
+        &'b mut self,
+        tree: &'b mut Tree,
+        layout: Layout<'b>,
+        renderer: &R,
+        viewport: &Rectangle,
+        translation: Vector,
+    ) -> Option<overlay::Element<'b, Message, Theme, R>> {
+        self.content.as_widget_mut().overlay(
+            &mut tree.children[0],
+            layout,
+            renderer,
+            viewport,
+            translation,
+        )
+    }
+}

crates/oa-desktop/src/model_menu.rs

@@ -415,7 +415,9 @@ pub fn popup(app: &App) -> Option<Menu<Message>> {
                     true,
                 ));
                 entries.push(item("Placement properties", Message::Select(node.id), true));
-                entries.push(item("Hide from this diagram", Message::HideSelected, true));
+                entries.push(
+                    item("Hide from this diagram", Message::HideSelected, true).shortcut("Delete"),
+                );
             } else if e.kind() != Kind::Port
                 && let Some(d) = app.active_diagram.and_then(|d| p.diagrams.get(&d))
             {
@@ -465,7 +467,25 @@ pub fn popup(app: &App) -> Option<Menu<Message>> {
             true,
         ));
         if id != p.id {
-            entries.push(item("Delete from model…", Message::Delete, true));
+            entries.push(
+                item("Delete from model…", Message::Delete, true).shortcut(
+                    if request.canvas.is_some_and(|context| context.diagram != id)
+                        && (request.placement.is_some()
+                            || p.relations.contains_key(&id)
+                            || p.elements
+                                .get(&id)
+                                .is_some_and(|element| element.kind() == Kind::Port))
+                    {
+                        if request.placement.is_some() {
+                            "Shift+Delete"
+                        } else {
+                            "Delete / Shift+Delete"
+                        }
+                    } else {
+                        ""
+                    },
+                ),
+            );
         }
     }
     Some(Menu {

crates/oa-desktop/src/views.rs

@@ -343,8 +343,8 @@ pub fn view(app: &App) -> View<'_, Message> {
             .into(),
         );
     }
-    if app.delete_pending {
-        return modal(root,column![text("Delete from model?").size(21),text(format!("{} and its owned elements will be removed. Incident relationships, occurrences and view placements are updated together. Counterparts in the other layer remain.",p.named(app.selected))).size(13),label("Undo restores the complete change. Use Hide for diagram-only removal."),row![action("Cancel",Message::CancelDelete),button("Delete from model").style(button::danger).padding(10).on_press(Message::ConfirmDelete)].spacing(10)].spacing(16).into());
+    if let Some(target) = app.delete_target.as_ref().filter(|_| app.delete_pending) {
+        return modal(root,column![text("Delete from model?").size(21),text(format!("{} and its owned elements will be removed. Incident relationships, occurrences and view placements are updated together. Counterparts in the other layer remain.",p.named(target.snapshot.request.object))).size(13),label("Undo restores the complete change. Use Hide for diagram-only removal."),row![action("Cancel",Message::CancelDelete),button("Delete from model").style(button::danger).padding(10).on_press(Message::ConfirmDelete(target.snapshot.token))].spacing(10)].spacing(16).into());
     }
     if app.pending.is_some() {
         return modal(root,column![text("Keep your changes?").size(21),text("Save the model and pending edits before continuing. Invalid drafts stay available for correction.").size(13),row![action("Cancel",Message::Cancel),action("Discard changes",Message::Discard),button("Save & continue").padding(10).on_press(Message::SaveAndContinue)].spacing(8)].spacing(16).into());
@@ -459,7 +459,12 @@ fn diagram(app: &App) -> View<'_, Message> {
             connection: app.connection.as_ref(),
         };
         let mut scene = widget::stack![
-            widget::canvas(program).width(Fill).height(Fill),
+            crate::diagram::focus::wrap(
+                widget::canvas(program).width(Fill).height(Fill),
+                program.context,
+                crate::app::diagram_removal::enabled(app),
+                Message::DiagramTraverse
+            ),
             widget::canvas(crate::diagram::PortLabels(program))
                 .width(Fill)
                 .height(Fill),

harness/diagram-delete-candidate-20260912.md

@@ -0,0 +1,63 @@
+# Diagram Delete candidate handoff — 2026-09-12
+
+Frozen, uncommitted implementation on `codex/diagram-delete-956atf-20260912`, isolated worktree `C:\Users\User\Documents\Git\ARCADIA-Studio\.local\diagram-delete-20260912`, HEAD/base `5a70181`. Parent owns issue 15 comment 551, review, Windows verification and integration. No Gitea, Git index/commit, compiler/cargo, native application, WSL or VPN operations performed by this worker. Files are ready for parent review/copy; do not interpret this as verified or complete issue 15.
+
+## Candidate behavior
+
+- Architecture OA/SA and persisted state diagrams: focused canvas Delete hides the selected explicit placement through ordinary `execute(Command::Delete(placement))`; semantic object remains. Shift+Delete opens the existing model-removal dialog. Visible architecture edges/ports and state transitions without explicit placements use confirmed model removal for Delete too.
+- Captured `diagram_removal::Intent` carries diagram document/revision/epoch, object and explicit placement. App independently checks clean draft/source/behavior, modal/menu/reference state, selected object/placement, current diagram/page/tool and visible projected membership. Keyboard path never calls `apply()`.
+- `diagram/focus.rs` supplies actual Iced Focusable ownership around the architecture/state canvas. It draws the existing behavior viewport style (1 px teal border) while keyboard-focused, without changing layout. It registers for standard focus operations; programmatic focus of any other field unfocuses it. It rejects captured/unfocused/disabled keys and resets at context/window boundaries. The old mouse-only DiagramCanvas.keyboard_focus and StateCanvas.focused gates were removed: the wrapper is the single keyboard authority. Standalone Program tests still exercise already-admitted events.
+- Canvas Tab uses ordinary Iced next/previous focus operations. A transient traversal flag rejects subsequent keys in the same native event batch before that task runs, while retaining focus for the operation's traversal count.
+- Delete requires selection mode and no active pointer/route/port/pan/work gesture. Existing bend Delete takes priority and a selected invalid bend cannot fall through to object removal. Unsupported modifiers are rejected. Diagram background is never a shortcut target.
+- A completed allocation work click retires its epoch before retained canvas state necessarily sees redraw. `diagram.rs` clears only an already-retired local work press before Delete; same-epoch/live work presses remain guarded. This avoids consuming the first Delete merely to send stale WorkDrag::Cancel. `diagram/work_drag.rs` and app/allocation_drag.rs are untouched.
+- Model confirmation is captured through existing model_menu::Opened plus selected identity/placement and a unique token. Rendered text uses the captured object. ConfirmDelete now requires the token. Cancel/Escape clear the snapshot and advance the canvas epoch. Old tokens cannot confirm a later dialog; changed document/revision/epoch/page/layer/diagram/object selection or placement refuses the command. Existing pointer/model menu deletion still invokes apply as before, then creates the captured confirmation.
+- Existing architecture/state menus gain scope-appropriate Delete/Shift+Delete hints. Diagram background and unsupported state-action rows do not claim a removal shortcut.
+
+## Changed files
+
+New:
+- `crates/oa-desktop/src/app/diagram_removal.rs` — intent validation, confirmation lifetime, shared keyboard admission predicate.
+- `crates/oa-desktop/src/diagram/focus.rs` — actual Iced Focusable wrapper.
+- `crates/oa-desktop/src/app/diagram_removal_tests.rs` — 10 mounted App-tree test functions.
+
+Modified:
+- `crates/oa-desktop/src/app.rs` — module/fields/messages, tokenized modal handling and focused delegation hunks.
+- `crates/oa-desktop/src/app/behavior_lifecycle_tests.rs` — existing ConfirmDelete constructor updated to token signature.
+- `crates/oa-desktop/src/app/state_diagram.rs` — delegates the captured removal event.
+- `crates/oa-desktop/src/behavior/state_canvas.rs` — admitted Delete events; removes obsolete private focus boolean.
+- `crates/oa-desktop/src/behavior/state_edit.rs` — captured removal event/context.
+- `crates/oa-desktop/src/behavior/state_menu.rs` — shortcut hints.
+- `crates/oa-desktop/src/behavior/state_view.rs` — focused wrapper.
+- `crates/oa-desktop/src/diagram.rs` — admitted Delete, bend/gesture priority, retired work-press cleanup; removes obsolete private focus boolean.
+- `crates/oa-desktop/src/model_menu.rs` — shortcut hints.
+- `crates/oa-desktop/src/views.rs` — captured confirmation text/token and architecture canvas wrapper only. Allocation toolbar region untouched.
+
+## Authored verification, not executed
+
+Reuses production `behavior::canvas_workspace::tests::Mounted`, real App::view/UserInterface/renderer, retained widget cache, ordered input batches and task/widget-operation draining. Tests never seed canvas private gesture or focus booleans.
+
+1. OA/SA real pointer selection → Delete exact placement; other diagram placement and semantic object retained; source/model agreement and complete one-unit Undo/Redo.
+2. Shift+Delete captured target; Cancel, Escape, old-token replay versus a new dialog; intended object removal and Undo source round trip.
+3. CLEAN Inspector focus by actual widget operation and canvas Tab; Tab+Delete in one native batch cannot remove model; Shift+Delete cannot reach canvas; Home/Delete edits Name while project/source remain accepted and unchanged.
+4. Captured emitted removal intent replay after selection, epoch, owner diagram, document or revision change.
+5. Window Unfocused, menu open/close, dirty draft, modal, epoch and unsupported modifier refusal, followed by explicit reacquisition.
+6. Real route-pin selection → Delete only bend; source round trip; actual edge segment selection → confirmed semantic deletion.
+7. Real state-canvas pointer selection → deletes state placement while architecture placement and state semantic object survive; Undo/source round trip.
+8. Captured confirmation refuses changed selection/document/epoch/placement/revision.
+9. Programmatic canvas focus without preceding mouse entry → Delete works through the single focus owner.
+10. OA/SA Allocation work body click → first Delete without intervening redraw hides exact placement once; semantic work/performer preserved; Undo restores source.
+
+Static checks performed: scoped rustfmt --edition 2024 --config skip_children=true on the 13 owned files; `git diff --check` passes. Formatter exit 0 is only a syntax-formatting check. No compilation or tests were run. Parent should run new `diagram_removal_tests` plus existing state/lifecycle, behavior lifecycle, model-menu, architecture and allocation full-tree tests on the combined integrated candidate.
+
+## Explicit remaining gaps / review risks
+
+- Process and scenario occurrence/link/fragment removal remains unimplemented; do not route their selections through architecture/state context or delete referenced reusable actors/functions. Scenario's modeled Delete participant event is untouched.
+- Explorer keyboard removal remains unimplemented; existing Actions/pointer menu remains available.
+- State action labels (state-action relation identities represented outside projected edges) remain pointer-menu deletion only. No shortcut hint is claimed for them.
+- Mounted tests have not executed. Inspector Tab order, route-segment geometry, state selection hit geometry and the allocation no-redraw case are particularly important concrete checks. No screenshot/native UI acceptance has been done.
+- Added tests exercise generated modal state and dispatch actual modal action messages through App; they do not locate/click the rendered confirmation buttons or read rendered glyph text. Parent native QA should confirm target wording and Cancel/Confirm accessibility.
+- Tool/gesture admission guards are authored, but dedicated new mounted drag/connection/creation/reconnect and stale-invalid-bend cases are not yet authored. Existing relevant regression tests should be retained and broadened if they expose missing coverage.
+- Intent validation compares current selection plus document/context lifetime. Switching selection away and back without any context/revision change is not recorded by a distinct selection-generation counter. Immediate changed-selection replay is covered. Parent should judge whether a stronger input-generation token is required for issue acceptance.
+- `delete_pending` boolean remains for compatibility with existing guards/tests; production opening always also creates delete_target. Legacy tests that manually set only the boolean do not create a rendered target dialog, though App modal admission still blocks underlying action messages.
+
+All candidate source files are frozen after this handoff. Further edits require parent follow-up.