diff --git a/CHANGELOG.md b/CHANGELOG.md
index 05145e09..edb76728 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -13,6 +13,7 @@
 - Added a central operator scope registry with current municipality names and NIS codes, including Mol `13025` and Nijlen `12026`.
 - Added an explicit, idempotent VRBG scope provisioner that creates one regional boundary, 28 member boundaries, one regional Area, 28 municipality Areas and canonical source datasets through the existing API.
 - Added a compact Mol/Kempen region selector to the map-first explorer and made its heading and full-area action scope-neutral.
+- Made region switches clear all project-bound state, ignore stale project-data responses and prefer the regional boundary/AOI, preventing Mol context from leaking into the Kempen workbench.
 - Kept thematic regional ingestion separate from the boundary pass so large GRB/WCS sources can be partitioned and validated without hidden startup fetches or truncated datasets.
 
 ## Sprint 188 Official modern Mol land-use series (2026-07-14)
diff --git a/backend/tests/test_sprint189_kempen_scope.py b/backend/tests/test_sprint189_kempen_scope.py
index 0dc94458..02163639 100644
--- a/backend/tests/test_sprint189_kempen_scope.py
+++ b/backend/tests/test_sprint189_kempen_scope.py
@@ -132,3 +132,17 @@ def test_kempen_scope_operator_is_packaged_and_exposed_in_map_flow() -> None:
     assert 'aria-label="Regio"' in workspace
     assert "projects={projects}" in app
     assert "onSelectProject={selectProject}" in app
+
+
+def test_project_switches_reset_scoped_state_and_prefer_the_regional_context() -> None:
+    bootstrap = (ROOT / "frontend/src/hooks/useWorkbenchBootstrap.ts").read_text(encoding="utf-8")
+    project_workspace = (ROOT / "frontend/src/hooks/useProjectWorkspace.ts").read_text(encoding="utf-8")
+    map_state = (ROOT / "frontend/src/hooks/useMapWorkspaceState.ts").read_text(encoding="utf-8")
+    dataset_workflow = (ROOT / "frontend/src/hooks/useDatasetWorkflow.ts").read_text(encoding="utf-8")
+
+    selected_project_branch = bootstrap.split("if (!selectedProjectId)", maxsplit=1)[1]
+    assert "resetProjectData()" in selected_project_branch
+    assert "resetDatasetForProject()" in selected_project_branch
+    assert "projectDataRequestSequence" in project_workspace
+    assert "vervoerregio|operationele grens" in map_state
+    assert "datasets.find(isOperationalScopeBoundaryDataset)" in dataset_workflow
diff --git a/frontend/src/hooks/useDatasetWorkflow.ts b/frontend/src/hooks/useDatasetWorkflow.ts
index b229df30..6b53a441 100644
--- a/frontend/src/hooks/useDatasetWorkflow.ts
+++ b/frontend/src/hooks/useDatasetWorkflow.ts
@@ -30,6 +30,14 @@ function toRasterMetadata(metadata: Record<string, unknown> | null | undefined):
   return metadata as unknown as RasterMetadataResponse
 }
 
+function isOperationalScopeBoundaryDataset(dataset: DatasetCreateResponse): boolean {
+  return (
+    dataset.status === 'ready' &&
+    (dataset.dataset_type === 'vector' || dataset.dataset_type === 'geojson') &&
+    dataset.source_metadata?.layer_type === 'regional_boundary'
+  )
+}
+
 function extractRasterTileManifestPath(job: JobRead | null | undefined): string {
   const manifest = toRasterTileHandoff(job)
   return manifest?.manifest_path ?? ''
@@ -131,6 +139,7 @@ export function useDatasetWorkflow({
     }
     // Auto-open the first usable dataset so Data, Map and Exports start with real context.
     const defaultDataset =
+      datasets.find(isOperationalScopeBoundaryDataset) ??
       datasets.find(isPrimaryFocusMunicipalityBoundaryDataset) ??
       datasets.find((dataset) => isVectorDatasetType(dataset.dataset_type) && dataset.status === 'ready') ??
       datasets.find((dataset) => dataset.status === 'ready') ??
diff --git a/frontend/src/hooks/useMapWorkspaceState.ts b/frontend/src/hooks/useMapWorkspaceState.ts
index cc85d75e..431c6b4d 100644
--- a/frontend/src/hooks/useMapWorkspaceState.ts
+++ b/frontend/src/hooks/useMapWorkspaceState.ts
@@ -31,9 +31,9 @@ export function useMapWorkspaceState({
     if (areas.length === 0) {
       setSelectedMapAreaId('')
     } else if (!selectedMapAreaId || !areas.some((area) => area.id === selectedMapAreaId)) {
-      const municipalityArea = areas.find((area) => /gemeente mol|municipality/i.test(area.name))
-      if (municipalityArea) {
-        setSelectedMapAreaId(municipalityArea.id)
+      const operationalScopeArea = areas.find((area) => /vervoerregio|operationele grens/i.test(area.name))
+      if (operationalScopeArea) {
+        setSelectedMapAreaId(operationalScopeArea.id)
       } else {
         const largestArea = [...areas].sort((left, right) => (right.area_m2 ?? 0) - (left.area_m2 ?? 0))[0]
         if (largestArea?.area_m2) {
diff --git a/frontend/src/hooks/useProjectWorkspace.ts b/frontend/src/hooks/useProjectWorkspace.ts
index 28a134a4..1e509f64 100644
--- a/frontend/src/hooks/useProjectWorkspace.ts
+++ b/frontend/src/hooks/useProjectWorkspace.ts
@@ -1,4 +1,4 @@
-import { FormEvent, useMemo, useState } from 'react'
+import { FormEvent, useMemo, useRef, useState } from 'react'
 import {
   PRIMARY_FOCUS_AREA_GEOJSON,
   PRIMARY_FOCUS_AREA_NAME,
@@ -46,6 +46,7 @@ export function useProjectWorkspace() {
   const [loadingAreas, setLoadingAreas] = useState(false)
   const [loadingDatasets, setLoadingDatasets] = useState(false)
   const [errorMessage, setErrorMessage] = useState<string | null>(null)
+  const projectDataRequestSequence = useRef(0)
 
   const [projectForm, setProjectForm] = useState<ProjectCreate>({
     name: '',
@@ -145,20 +146,28 @@ export function useProjectWorkspace() {
   }
 
   const loadProjectData = async (projectId: string) => {
+    const requestId = ++projectDataRequestSequence.current
     setLoadingAreas(true)
     setLoadingDatasets(true)
     setErrorMessage(null)
     try {
       const projectData = await fetchProjectData(projectId)
+      if (requestId !== projectDataRequestSequence.current) {
+        return null
+      }
       setAreas(projectData.areas)
       setDatasets(projectData.datasets)
       return projectData
     } catch (error) {
-      setErrorMessage(error instanceof Error ? error.message : 'Failed to load project data')
+      if (requestId === projectDataRequestSequence.current) {
+        setErrorMessage(error instanceof Error ? error.message : 'Failed to load project data')
+      }
       return null
     } finally {
-      setLoadingAreas(false)
-      setLoadingDatasets(false)
+      if (requestId === projectDataRequestSequence.current) {
+        setLoadingAreas(false)
+        setLoadingDatasets(false)
+      }
     }
   }
 
@@ -209,6 +218,7 @@ export function useProjectWorkspace() {
   }
 
   const resetProjectData = () => {
+    projectDataRequestSequence.current += 1
     setAreas([])
     setDatasets([])
   }
diff --git a/frontend/src/hooks/useWorkbenchBootstrap.ts b/frontend/src/hooks/useWorkbenchBootstrap.ts
index 9502b07d..f8423f51 100644
--- a/frontend/src/hooks/useWorkbenchBootstrap.ts
+++ b/frontend/src/hooks/useWorkbenchBootstrap.ts
@@ -70,6 +70,11 @@ export function useWorkbenchBootstrap({
       resetExportsForProject()
       return
     }
+    resetProjectData()
+    resetDatasetForProject()
+    resetDetectionForProject()
+    resetSegmentationForProject()
+    resetExportsForProject()
     loadProjectData(selectedProjectId).catch(() => null)
     loadDetectionRuns(selectedProjectId).catch(() => null)
     loadSegmentationRuns(selectedProjectId).catch(() => null)