endrix · endrix · Oct 2, 2026 · Oct 2, 2026
diff --git a/docs/proposals/single-editor-hierarchy.md b/docs/proposals/single-editor-hierarchy.md
@@ -1,6 +1,6 @@
 # Proposal: one editor for a whole workflow hierarchy
 
-**Status:** phases 1 to 3 are implemented (in-place navigation, the root's run, the view in the chat's context, and editing nested views). Phases 4 and 5 (per-instance layout, the hierarchy export and the outline) are not.
+**Status:** phases 1 to 4 are implemented (in-place navigation, the root's run, the view in the chat's context, editing nested views, and per-instance layout). Phase 5 (the hierarchy export and the outline) is not.
 **Affects:** dialogram (most of it), wfpy (a hierarchy export), wfpy-ide (one
 profile flag).
 
@@ -222,8 +222,17 @@ comes from the same export, and is the cheap part of it: names, files and sizes.
    changed. A save or an on-disk change already refreshed every editor, and now
    reaches the view shown. Unsaved edits to a nested file preview in the views
    showing it.
-4. **Layout per instance**, in the root's layout file, falling back to the
-   defining file's.
+4. **Layout per instance.** *Done.* With `nestedNavigation: 'in-place'`
+   (now also in the storage options), a view at a trail of two or more crumbs
+   reads its layout from the root file's store, keyed
+   `root/<instance path>/<workflow>` (`layout-target.ts`). Until it has one, it
+   starts from the workflow's standalone layout. The target is recorded on the
+   diagram model at load (`layoutTarget`), and every handler that saves a
+   layout uses it (`layoutTargetOf`): moving a node, rerouting, resetting
+   routes, the layout commands, placing new nodes. Eight of them had each
+   recomputed the key from the shown workflow's name, so a hierarchical
+   runtime's per-instance layouts were read per instance and saved per
+   workflow. A rename also moves the node in the instance's layout.
 5. **The hierarchy export, the cache and the outline.** wfpy `--hierarchy`,
    instance-elaborated nested graphs, the server cache, then the outline panel.
 

diff --git a/packages/diagram-server/src/operations/change-bounds-handler.ts b/packages/diagram-server/src/operations/change-bounds-handler.ts
@@ -10,7 +10,6 @@ import { GEdge, GNode, GPort } from '@eclipse-glsp/graph';
 import { ChangeBoundsOperation } from '@eclipse-glsp/protocol';
 import { GModelChangeBoundsOperationHandler, GModelSerializer, GModelRecordingCommand, type Command, type MaybePromise } from '@eclipse-glsp/server';
 import { inject, injectable } from 'inversify';
-import { URI } from 'vscode-uri';
 
 import { WorkflowDiagramMetadata } from '@dialogram/shared';
 import { LayoutPersistenceService } from '../services/layout-persistence-service';
@@ -20,6 +19,7 @@ import {
     WORKFLOW_REROUTE_EDGES_AVOID_OVERLAPS_OPERATION_KIND,
     WorkflowRerouteEdgesAvoidOverlapsOperationHandler
 } from './reroute-edges-avoid-overlaps-handler';
+import { layoutTargetOf } from '../server/layout-target';
 
 @injectable()
 export class WorkflowChangeBoundsOperationHandler extends GModelChangeBoundsOperationHandler {
@@ -66,8 +66,7 @@ export class WorkflowChangeBoundsOperationHandler extends GModelChangeBoundsOper
             return;
         }
 
-        const workflowFilePath = URI.parse(diagramModel.documentUri).fsPath;
-        const networkId = this.getNetworkId(diagramModel);
+        const { filePath: workflowFilePath, networkId } = layoutTargetOf(diagramModel as any);
 
         void (async () => {
             const positions = (await this.layoutPersistence.loadLayout(workflowFilePath, networkId)) ?? new Map();
@@ -197,12 +196,4 @@ export class WorkflowChangeBoundsOperationHandler extends GModelChangeBoundsOper
         }
         return undefined;
     }
-
-    private getNetworkId(diagramModel: WorkflowDiagramModel): string {
-        const explicit = (diagramModel as any)?.workflowName as string | undefined;
-        if (typeof explicit === 'string' && explicit.trim() !== '') {
-            return explicit.trim();
-        }
-        return 'unknown';
-    }
 }
diff --git a/packages/diagram-server/src/operations/change-routing-points-handler.ts b/packages/diagram-server/src/operations/change-routing-points-handler.ts
@@ -10,14 +10,14 @@ import {
     type MaybePromise
 } from '@eclipse-glsp/server';
 import { inject, injectable } from 'inversify';
-import { URI } from 'vscode-uri';
 
 import { WorkflowDiagramMetadata } from '@dialogram/shared';
 import { LayoutPersistenceService } from '../services/layout-persistence-service';
 import { WORKFLOW_LAYOUT_PERSISTENCE_KEY, WORKFLOW_NETWORK_MODEL_KEY } from '@dialogram/shared';
 import { WorkflowDiagramConstants } from '@dialogram/shared';
 import type { WorkflowDiagramModel } from '@dialogram/shared';
 import { GModelSerializer } from '@eclipse-glsp/server';
+import { layoutTargetOf } from '../server/layout-target';
 
 @injectable()
 export class WorkflowChangeRoutingPointsOperationHandler extends OperationHandler {
@@ -280,11 +280,7 @@ export class WorkflowChangeRoutingPointsOperationHandler extends OperationHandle
             return;
         }
 
-        const workflowFilePath = URI.parse(diagramModel.documentUri).fsPath;
-        const explicitName = (diagramModel as any).workflowName as string | undefined;
-        const networkId = explicitName && explicitName.trim() !== ''
-            ? explicitName.trim()
-            : 'unknown';
+        const { filePath: workflowFilePath, networkId } = layoutTargetOf(diagramModel as any);
 
         // Prefer persisted positions (stable keys) and only update routes.
         const persistedPositions = await this.layoutPersistence.loadLayout(workflowFilePath, networkId);

diff --git a/packages/diagram-server/src/operations/layout-boundary-flow-handler.ts b/packages/diagram-server/src/operations/layout-boundary-flow-handler.ts
@@ -11,7 +11,6 @@ import {
     GModelSerializer
 } from '@eclipse-glsp/server';
 import { inject, injectable, optional } from 'inversify';
-import { URI } from 'vscode-uri';
 import { LayoutPersistenceService } from '../services/layout-persistence-service';
 import { WORKFLOW_LAYOUT_PERSISTENCE_KEY, WORKFLOW_NETWORK_MODEL_KEY } from '@dialogram/shared';
 import type { WorkflowDiagramModel } from '@dialogram/shared';
@@ -22,6 +21,7 @@ import {
     WORKFLOW_REROUTE_EDGES_AVOID_OVERLAPS_OPERATION_KIND,
     WorkflowRerouteEdgesAvoidOverlapsOperationHandler
 } from './reroute-edges-avoid-overlaps-handler';
+import { layoutTargetOf } from '../server/layout-target';
 
 export const WORKFLOW_LAYOUT_BOUNDARY_FLOW_OPERATION_KIND = 'dialogram.layoutBoundaryFlow' as const;
 
@@ -94,11 +94,7 @@ export class WorkflowLayoutBoundaryFlowOperationHandler extends OperationHandler
             return;
         }
 
-        const workflowFilePath = URI.parse(diagramModel.documentUri).fsPath;
-        const explicitName = (diagramModel as any).workflowName as string | undefined;
-        const networkId = explicitName && explicitName.trim() !== ''
-            ? explicitName.trim()
-            : 'unknown';
+        const { filePath: workflowFilePath, networkId } = layoutTargetOf(diagramModel as any);
         const positions = this.collectNodePositions(this.modelState.root);
         const routes = this.collectEdgeRoutes(this.modelState.root);
         await this.layoutPersistence.saveLayoutImmediate(workflowFilePath, networkId, positions, routes);

diff --git a/packages/diagram-server/src/operations/layout-serpentine-mesh-handler.ts b/packages/diagram-server/src/operations/layout-serpentine-mesh-handler.ts
@@ -14,7 +14,6 @@ import {
     GModelSerializer
 } from '@eclipse-glsp/server';
 import { inject, injectable, optional } from 'inversify';
-import { URI } from 'vscode-uri';
 import { LayoutPersistenceService } from '../services/layout-persistence-service';
 import {
     WorkflowRerouteEdgesAvoidOverlapsOperationHandler,
@@ -24,6 +23,7 @@ import { WORKFLOW_LAYOUT_PERSISTENCE_KEY, WORKFLOW_NETWORK_MODEL_KEY } from '@di
 import type { WorkflowDiagramModel } from '@dialogram/shared';
 import { WorkflowDiagramMetadata, WorkflowDiagramTypes } from '@dialogram/shared';
 import { WorkflowDiagramConstants } from '@dialogram/shared';
+import { layoutTargetOf } from '../server/layout-target';
 
 export const WORKFLOW_LAYOUT_SERPENTINE_MESH_OPERATION_KIND = 'dialogram.layoutSerpentineMesh' as const;
 
@@ -95,11 +95,7 @@ export class WorkflowLayoutSerpentineMeshOperationHandler extends OperationHandl
             return;
         }
 
-        const workflowFilePath = URI.parse(diagramModel.documentUri).fsPath;
-        const explicitName = (diagramModel as any).workflowName as string | undefined;
-        const networkId = explicitName && explicitName.trim() !== ''
-            ? explicitName.trim()
-            : 'unknown';
+        const { filePath: workflowFilePath, networkId } = layoutTargetOf(diagramModel as any);
         const positions = this.collectNodePositions(this.modelState.root);
         const routes = this.collectEdgeRoutes(this.modelState.root);
         await this.layoutPersistence.saveLayoutImmediate(workflowFilePath, networkId, positions, routes);

diff --git a/packages/diagram-server/src/operations/reroute-edges-avoid-overlaps-handler.ts b/packages/diagram-server/src/operations/reroute-edges-avoid-overlaps-handler.ts
@@ -11,14 +11,14 @@ import {
     type MaybePromise
 } from '@eclipse-glsp/server';
 import { inject, injectable } from 'inversify';
-import { URI } from 'vscode-uri';
 import { LayoutPersistenceService } from '../services/layout-persistence-service';
 import { WORKFLOW_NETWORK_MODEL_KEY } from '@dialogram/shared';
 import type { WorkflowDiagramModel } from '@dialogram/shared';
 import { WorkflowDiagramMetadata } from '@dialogram/shared';
 import { WorkflowDiagramConstants, portAnchor } from '@dialogram/shared';
 import { GModelSerializer } from '@eclipse-glsp/server';
 import { routeOrthogonal, type RouterConnector, type RouterObstacle } from '../routing/libavoid-router';
+import { layoutTargetOf } from '../server/layout-target';
 
 /** Every segment axis-aligned? A diagonal means the polyline is not a valid route. */
 export function isOrthogonalPolyline(points: readonly { x: number; y: number }[]): boolean {
@@ -1029,8 +1029,7 @@ export class WorkflowRerouteEdgesAvoidOverlapsOperationHandler extends Operation
                 if (!operation.preview) {
                     const dm = this.modelState.get(WORKFLOW_NETWORK_MODEL_KEY) as WorkflowDiagramModel | undefined;
                     if (dm) {
-                        const workflowFilePath = URI.parse(dm.documentUri).fsPath;
-                        const networkId = (dm as any).workflowName ?? 'unknown';
+                        const { filePath: workflowFilePath, networkId } = layoutTargetOf(dm as any);
                         const positions = this.collectNodePositions(root);
                         const routes = this.collectEdgeRoutes(root);
                         await this.layoutPersistence.saveLayoutImmediate(workflowFilePath, networkId, positions, routes);
@@ -1232,8 +1231,7 @@ export class WorkflowRerouteEdgesAvoidOverlapsOperationHandler extends Operation
         const dm = this.modelState.get(WORKFLOW_NETWORK_MODEL_KEY) as WorkflowDiagramModel | undefined;
         if (!dm) { return; }
 
-        const workflowFilePath = URI.parse(dm.documentUri).fsPath;
-        const networkId = (dm as any).workflowName ?? 'unknown';
+        const { filePath: workflowFilePath, networkId } = layoutTargetOf(dm as any);
 
         const positions = this.collectNodePositions(root);
         const routes = this.collectEdgeRoutes(root);

diff --git a/packages/diagram-server/src/operations/reset-edge-routes-handler.ts b/packages/diagram-server/src/operations/reset-edge-routes-handler.ts
@@ -8,12 +8,12 @@ import {
     type MaybePromise
 } from '@eclipse-glsp/server';
 import { inject, injectable } from 'inversify';
-import { URI } from 'vscode-uri';
 import { LayoutPersistenceService } from '../services/layout-persistence-service';
 import { WORKFLOW_NETWORK_MODEL_KEY } from '@dialogram/shared';
 import type { WorkflowDiagramModel } from '@dialogram/shared';
 import { WorkflowDiagramMetadata } from '@dialogram/shared';
 import { GModelSerializer } from '@eclipse-glsp/server';
+import { layoutTargetOf } from '../server/layout-target';
 
 export const WORKFLOW_RESET_EDGE_ROUTES_OPERATION_KIND = 'dialogram.resetEdgeRoutes' as const;
 
@@ -119,11 +119,7 @@ export class WorkflowResetEdgeRoutesOperationHandler extends OperationHandler {
             return;
         }
 
-        const workflowFilePath = URI.parse(diagramModel.documentUri).fsPath;
-        const explicitName = (diagramModel as any).workflowName as string | undefined;
-        const networkId = explicitName && explicitName.trim() !== ''
-            ? explicitName.trim()
-            : 'unknown';
+        const { filePath: workflowFilePath, networkId } = layoutTargetOf(diagramModel as any);
 
         // Prefer the already-persisted node map (it uses stable keys), falling back to the
         // current model snapshot if no layout file exists yet.

diff --git a/packages/diagram-server/src/server/diagram-action-handlers.ts b/packages/diagram-server/src/server/diagram-action-handlers.ts
@@ -41,7 +41,6 @@ import {
     UpdateModelAction
 } from '@eclipse-glsp/protocol';
 import { inject, injectable, optional } from 'inversify';
-import { URI } from 'vscode-uri';
 import {
     WorkflowDiagramMetadata,
     type WorkflowDiagramModel,
@@ -59,6 +58,7 @@ import {
 import { clearAllEdgeRoutingPoints } from '../routing/clear-edge-routes';
 import { releaseBoundaryNodeConstraints, restoreNodeLayoutOptions, runBoundaryFlowLayout } from '../operations/boundary-flow-layout';
 import { perfNow } from './graph-load-perf';
+import { layoutTargetOf } from './layout-target';
 
 /**
  * Custom ModelSubmissionHandler - minimal logging version.
@@ -1747,11 +1747,7 @@ export class WorkflowLayoutOperationHandler extends OperationHandler {
             return;
         }
 
-        const workflowFilePath = URI.parse(diagramModel.documentUri).fsPath;
-        const explicitName = (diagramModel as any)?.workflowName as string | undefined;
-        const networkId = explicitName && explicitName.trim() !== ''
-            ? explicitName.trim()
-            : 'unknown';
+        const { filePath: workflowFilePath, networkId } = layoutTargetOf(diagramModel as any);
         const positions = this.collectNodePositions(this.modelState.root);
         const routes = this.collectEdgeRoutes(this.modelState.root);
         await this.layoutPersistence.saveLayoutImmediate(workflowFilePath, networkId, positions, routes);

diff --git a/packages/diagram-server/src/server/layout-target.ts b/packages/diagram-server/src/server/layout-target.ts
@@ -0,0 +1,82 @@
+/**
+ * Where a view's layout lives, and under which key.
+ *
+ * A workflow shown on its own keeps its layout in its file's layout store,
+ * keyed by its name. A nested workflow shown in place, as a view of an editor's
+ * root, is an *instance*: its layout belongs to the root, in the root file's
+ * store, keyed by the instance path from the root (`top/b2/block`). Two uses of
+ * one workflow can then be arranged differently, and the root owns the layout
+ * of everything it shows.
+ *
+ * An instance with no layout of its own yet starts from the workflow's
+ * standalone layout, so every layout made before keeps applying.
+ */
+
+import { URI } from 'vscode-uri';
+
+export interface LayoutTarget {
+    /** The source file whose layout store holds it. */
+    filePath: string;
+    /** The key inside that store. */
+    networkId: string;
+}
+
+export interface InstanceLayout {
+    target: LayoutTarget;
+    /** Read when the target holds nothing yet: the workflow's standalone layout. */
+    fallback: LayoutTarget;
+}
+
+export interface TrailCrumb {
+    sourceUri: string;
+    workflowName: string;
+    workflowInstanceName?: string;
+}
+
+/**
+ * The instance layout for a view at `trail`, or nothing when the view is a
+ * root (a trail of one, or none) or the trail does not end at it.
+ */
+export function instanceLayoutFor(
+    trail: TrailCrumb[],
+    shown: { filePath: string; workflowName: string },
+    toFilePath: (sourceUri: string) => string
+): InstanceLayout | undefined {
+    if (trail.length < 2) {
+        return undefined;
+    }
+    const root = trail[0];
+    const last = trail[trail.length - 1];
+    if (last.workflowName !== shown.workflowName || toFilePath(last.sourceUri) !== shown.filePath) {
+        return undefined;
+    }
+    const instancePath = trail.slice(1).map(crumb => crumb.workflowInstanceName?.trim() || crumb.workflowName);
+    return {
+        target: {
+            filePath: toFilePath(root.sourceUri),
+            // The shape a hierarchical runtime's layouts already use:
+            // root, instance path, then the workflow shown.
+            networkId: [root.workflowName, ...instancePath, shown.workflowName].join('/')
+        },
+        fallback: { filePath: shown.filePath, networkId: shown.workflowName }
+    };
+}
+
+/**
+ * The layout target of the loaded view: where its layout is read from and
+ * saved to. Recorded on the diagram model at load (`layoutTarget`) -- the
+ * instance target for a nested view in place, or a hierarchical runtime's --
+ * so every handler that saves a layout saves it where it was read. Without one,
+ * the shown file and workflow, as handlers computed it before.
+ */
+export function layoutTargetOf(
+    diagramModel: { documentUri: string; workflowName?: unknown; layoutTarget?: LayoutTarget }
+): LayoutTarget {
+    if (diagramModel.layoutTarget) {
+        return diagramModel.layoutTarget;
+    }
+    const name = typeof diagramModel.workflowName === 'string' && diagramModel.workflowName.trim() !== ''
+        ? diagramModel.workflowName.trim()
+        : 'unknown';
+    return { filePath: URI.parse(diagramModel.documentUri).fsPath, networkId: name };
+}
diff --git a/packages/diagram-server/src/server/source-model-storage.ts b/packages/diagram-server/src/server/source-model-storage.ts
@@ -17,6 +17,7 @@ import {
 import { RequestModelAction, SaveModelAction } from '@eclipse-glsp/protocol';
 import { inject, injectable, optional } from 'inversify';
 import { URI } from 'vscode-uri';
+import { instanceLayoutFor, type LayoutTarget } from './layout-target';
 import * as path from 'node:path';
 import { promises as fs } from 'node:fs';
 import {
@@ -440,7 +441,7 @@ export class WorkflowSourceModelStorage implements SourceModelStorage {
         (diagramModel as any).workflowName = workflowName;
         (diagramModel as any).documentUri = sourceUri;
 
-        const workflowFilePath = filePath;
+        let workflowFilePath = filePath;
         // Qualify hierarchical network IDs so each instance-path gets its own layout
         // (e.g. "qwen35_model/decoder_block/decoder_layer"). Only a hierarchical runtime ever
         // supplies the root-workflow arg, so gating on its presence (rather than the settings
@@ -449,13 +450,32 @@ export class WorkflowSourceModelStorage implements SourceModelStorage {
         const hierarchicalRoot = typeof opts[ROOT_WORKFLOW_ARG] === 'string' && String(opts[ROOT_WORKFLOW_ARG]).trim() !== ''
             ? String(opts[ROOT_WORKFLOW_ARG]).trim()
             : undefined;
+        let fallbackLayout: LayoutTarget | undefined;
         if (hierarchicalRoot) {
             const hierarchicalInstancePath = parseStringListArg(opts[INSTANCE_PATH_ARG]);
             const parts = [hierarchicalRoot, ...hierarchicalInstancePath, networkId];
             networkId = parts.join('/');
+        } else if (this.storageOptions?.nestedNavigation === 'in-place') {
+            // A nested workflow shown in place is an instance of the editor's
+            // root: its layout is the root's, per instance, falling back to the
+            // workflow's standalone layout until it has one of its own.
+            const instance = instanceLayoutFor(
+                this.parseNavigationTrailArg(opts[NAV_TRAIL_ARG]),
+                { filePath: workflowFilePath, workflowName: networkId },
+                uri => URI.parse(uri).fsPath
+            );
+            if (instance) {
+                workflowFilePath = instance.target.filePath;
+                networkId = instance.target.networkId;
+                fallbackLayout = instance.fallback;
+            }
+        }
+        let loadedLayoutPositions = await this.layoutPersistence.loadLayout(workflowFilePath, networkId);
+        let edgeRoutes = await this.layoutPersistence.loadEdgeRoutes(workflowFilePath, networkId);
+        if (!loadedLayoutPositions && fallbackLayout) {
+            loadedLayoutPositions = await this.layoutPersistence.loadLayout(fallbackLayout.filePath, fallbackLayout.networkId);
+            edgeRoutes = await this.layoutPersistence.loadEdgeRoutes(fallbackLayout.filePath, fallbackLayout.networkId);
         }
-        const loadedLayoutPositions = await this.layoutPersistence.loadLayout(workflowFilePath, networkId);
-        const edgeRoutes = await this.layoutPersistence.loadEdgeRoutes(workflowFilePath, networkId);
         const hasPersistedEdgeRoutes = edgeRoutes !== undefined;
         perf?.mark('layoutIO');
 
@@ -519,6 +539,9 @@ export class WorkflowSourceModelStorage implements SourceModelStorage {
         );
         const hasPersistedEdgeRoutesEffective = hasPersistedLayout && hasPersistedEdgeRoutes;
 
+        // Where every handler that saves this view's layout saves it.
+        (diagramModel as any).layoutTarget = { filePath: workflowFilePath, networkId };
+
         this.modelState.set(WORKFLOW_LAYOUT_PERSISTENCE_KEY, {
             workflowFilePath,
             networkId,