diff --git a/actions/active-sprint.ts b/actions/active-sprint.ts
index b0fbb75..e774376 100644
--- a/actions/active-sprint.ts
+++ b/actions/active-sprint.ts
@@ -9,6 +9,7 @@ import { SessionData, sessionOptions } from '@/lib/session'
 import { productAccessFilter } from '@/lib/product-access'
 import {
   clearActiveSprintInSettings,
+  setActiveSelectionInSettings,
   setActiveSprintInSettings,
 } from '@/lib/active-sprint'
 
@@ -67,6 +68,80 @@ export async function clearActiveSprintAction(productId: string) {
   return { success: true }
 }
 
+const selectionSchema = z.object({
+  productId: z.string().min(1),
+  sprintId: z.string().min(1),
+})
+
+/**
+ * PBI-79: kies een sprint en auto-select zijn enige PBI/story (indien
+ * singleton). Resultaat wordt server-side bepaald + atomair in user-settings
+ * weggeschreven (sprint+pbi+story) zodat cross-device-restore klopt.
+ */
+export async function switchActiveSprintAction(
+  productId: string,
+  sprintId: string,
+): Promise<
+  | {
+      success: true
+      sprintId: string
+      pbiId: string | null
+      storyId: string | null
+    }
+  | { error: string }
+> {
+  const session = await getSession()
+  if (!session.userId) return { error: 'Niet ingelogd' }
+  if (session.isDemo) return { error: 'Niet beschikbaar in demo-modus' }
+
+  const parsed = selectionSchema.safeParse({ productId, sprintId })
+  if (!parsed.success) return { error: 'Ongeldig product- of sprint-id' }
+
+  const sprint = await prisma.sprint.findFirst({
+    where: {
+      id: parsed.data.sprintId,
+      product_id: parsed.data.productId,
+      product: productAccessFilter(session.userId),
+    },
+    select: { id: true },
+  })
+  if (!sprint) return { error: 'Sprint niet gevonden of niet toegankelijk' }
+
+  // Auto-select: alleen wanneer sprint exact één PBI heeft. Story-auto-select
+  // alleen wanneer die PBI exact één story binnen deze sprint heeft.
+  const sprintStories = await prisma.story.findMany({
+    where: {
+      sprint_id: parsed.data.sprintId,
+      product_id: parsed.data.productId,
+    },
+    select: { id: true, pbi_id: true },
+  })
+  const uniquePbiIds = Array.from(new Set(sprintStories.map((s) => s.pbi_id)))
+  let autoPbiId: string | null = null
+  let autoStoryId: string | null = null
+  if (uniquePbiIds.length === 1) {
+    autoPbiId = uniquePbiIds[0]
+    const storiesForPbi = sprintStories.filter((s) => s.pbi_id === autoPbiId)
+    if (storiesForPbi.length === 1) {
+      autoStoryId = storiesForPbi[0].id
+    }
+  }
+
+  await setActiveSelectionInSettings(session.userId, parsed.data.productId, {
+    sprintId: parsed.data.sprintId,
+    pbiId: autoPbiId,
+    storyId: autoStoryId,
+  })
+  revalidatePath('/', 'layout')
+
+  return {
+    success: true,
+    sprintId: parsed.data.sprintId,
+    pbiId: autoPbiId,
+    storyId: autoStoryId,
+  }
+}
+
 export async function syncActiveSprintCookieAction(productId: string, sprintId: string) {
   const session = await getSession()
   if (!session.userId) return
diff --git a/app/(app)/products/[id]/page.tsx b/app/(app)/products/[id]/page.tsx
index 4288882..1b52c7a 100644
--- a/app/(app)/products/[id]/page.tsx
+++ b/app/(app)/products/[id]/page.tsx
@@ -18,6 +18,7 @@ import { TaskDialogSkeleton } from '@/app/_components/tasks/task-dialog-skeleton
 import { NewSprintTrigger } from '@/components/backlog/new-sprint-trigger'
 import { SprintDraftBanner } from '@/components/backlog/sprint-draft-banner'
 import { SaveSprintButton } from '@/components/backlog/save-sprint-button'
+import { ActiveSelectionHydrator } from '@/components/backlog/active-selection-hydrator'
 import { ActivateProductButton } from '@/components/shared/activate-product-button'
 import { EditProductButton } from '@/components/products/edit-product-button'
 import { SprintSwitcher } from '@/components/shared/sprint-switcher'
@@ -166,6 +167,7 @@ export default async function ProductBacklogPage({ params, searchParams }: Props
           }}
         >
           <UrlTaskSync />
+          <ActiveSelectionHydrator productId={id} />
           <BacklogSplitPane
             cookieKey={`backlog-${id}`}
             defaultSplit={[20, 45, 35]}
diff --git a/components/backlog/active-selection-hydrator.tsx b/components/backlog/active-selection-hydrator.tsx
new file mode 100644
index 0000000..966b672
--- /dev/null
+++ b/components/backlog/active-selection-hydrator.tsx
@@ -0,0 +1,53 @@
+'use client'
+
+import { useEffect } from 'react'
+import { useUserSettingsStore } from '@/stores/user-settings/store'
+import { useProductWorkspaceStore } from '@/stores/product-workspace/store'
+
+interface ActiveSelectionHydratorProps {
+  productId: string
+}
+
+/**
+ * PBI-79: hydrateert de workspace-store met de actieve PBI/story die in
+ * user-settings staan opgeslagen. Loopt na elke (re)hydratatie en bij
+ * mutaties van de user-settings (bv. na sprint-switch). Wint van de
+ * localStorage hint-restore — user-settings is de cross-device source of
+ * truth.
+ */
+export function ActiveSelectionHydrator({ productId }: ActiveSelectionHydratorProps) {
+  const hydrated = useUserSettingsStore((s) => s.context.hydrated)
+  const persistedPbiId = useUserSettingsStore(
+    (s) => s.entities.settings.layout?.activePbis?.[productId] ?? undefined,
+  )
+  const persistedStoryId = useUserSettingsStore(
+    (s) => s.entities.settings.layout?.activeStories?.[productId] ?? undefined,
+  )
+
+  useEffect(() => {
+    if (!hydrated) return
+    const store = useProductWorkspaceStore.getState()
+    // Schrijf alleen wanneer user-settings expliciet iets gekozen heeft
+    // (key aanwezig met string-waarde). null-key betekent 'bewust leeg' →
+    // we wissen lokale state. undefined-key (geen voorkeur) → niets doen.
+    if (persistedPbiId === undefined && persistedStoryId === undefined) return
+
+    if (persistedPbiId === null) {
+      store.setActivePbi(null)
+      return
+    }
+    if (persistedPbiId && store.context.activePbiId !== persistedPbiId) {
+      store.setActivePbi(persistedPbiId)
+    }
+    if (persistedStoryId && store.context.activeStoryId !== persistedStoryId) {
+      // setActivePbi triggert async cascade-restore die de oude hint kan
+      // herstellen; de daarop volgende setActiveStory bumpt activeRequestId
+      // en ongeldigt de cascade.
+      store.setActiveStory(persistedStoryId)
+    } else if (persistedStoryId === null) {
+      store.setActiveStory(null)
+    }
+  }, [hydrated, persistedPbiId, persistedStoryId])
+
+  return null
+}
diff --git a/components/shared/sprint-switcher.tsx b/components/shared/sprint-switcher.tsx
index d0ada8d..d809fa1 100644
--- a/components/shared/sprint-switcher.tsx
+++ b/components/shared/sprint-switcher.tsx
@@ -13,7 +13,11 @@ import {
   DropdownMenuTrigger,
 } from '@/components/ui/dropdown-menu'
 import { cn } from '@/lib/utils'
-import { clearActiveSprintAction, setActiveSprintAction } from '@/actions/active-sprint'
+import {
+  clearActiveSprintAction,
+  switchActiveSprintAction,
+} from '@/actions/active-sprint'
+import { useProductWorkspaceStore } from '@/stores/product-workspace/store'
 import type { SprintStatusApi } from '@/lib/task-status'
 import { debugProps } from '@/lib/debug'
 
@@ -54,11 +58,25 @@ export function SprintSwitcher({
   function handleSwitchSprint(sprintId: string) {
     if (sprintId === activeSprint?.id) return
     startTransition(async () => {
-      const result = await setActiveSprintAction(productId, sprintId)
-      if (result?.error) {
-        toast.error(typeof result.error === 'string' ? result.error : 'Wisselen mislukt')
+      const result = await switchActiveSprintAction(productId, sprintId)
+      if ('error' in result) {
+        toast.error(
+          typeof result.error === 'string' ? result.error : 'Wisselen mislukt',
+        )
         return
       }
+      // Synchroniseer de client-side workspace-store met de auto-select die
+      // server-side is bepaald — voorkomt korte flash van vorige selectie
+      // voordat router.refresh de SSR-render binnenhaalt.
+      const store = useProductWorkspaceStore.getState()
+      if (result.pbiId) {
+        store.setActivePbi(result.pbiId)
+        if (result.storyId) {
+          store.setActiveStory(result.storyId)
+        }
+      } else {
+        store.setActivePbi(null)
+      }
       if (pathname.includes('/sprint')) {
         router.push(`/products/${productId}/sprint/${sprintId}`)
       } else {
diff --git a/lib/active-sprint.ts b/lib/active-sprint.ts
index 4ca3234..a5e6033 100644
--- a/lib/active-sprint.ts
+++ b/lib/active-sprint.ts
@@ -93,6 +93,57 @@ export async function clearActiveSprintInSettings(
   })
 }
 
+/**
+ * PBI-79: persisteer sprint-keuze + bijbehorende PBI/story-selectie atomair.
+ * Sprintkeuze blijft 'sleutel met null = bewust geen sprint'-contract trouw;
+ * activePbi/activeStory volgen dezelfde semantiek (null = expliciet leeg).
+ */
+export async function setActiveSelectionInSettings(
+  userId: string,
+  productId: string,
+  selection: {
+    sprintId: string | null
+    pbiId?: string | null
+    storyId?: string | null
+  },
+): Promise<void> {
+  const current = await readSettings(userId)
+  const nextActiveSprints: Record<string, string | null> = {
+    ...(current.layout?.activeSprints ?? {}),
+    [productId]: selection.sprintId,
+  }
+  const nextActivePbis: Record<string, string | null> = {
+    ...(current.layout?.activePbis ?? {}),
+  }
+  if (selection.pbiId !== undefined) {
+    nextActivePbis[productId] = selection.pbiId
+  }
+  const nextActiveStories: Record<string, string | null> = {
+    ...(current.layout?.activeStories ?? {}),
+  }
+  if (selection.storyId !== undefined) {
+    nextActiveStories[productId] = selection.storyId
+  }
+
+  const next: UserSettings = {
+    ...current,
+    layout: {
+      ...current.layout,
+      activeSprints: nextActiveSprints,
+      activePbis: nextActivePbis,
+      activeStories: nextActiveStories,
+    },
+  }
+  await writeSettings(userId, next)
+  await notifyUserSettings(userId, {
+    layout: {
+      activeSprints: nextActiveSprints,
+      activePbis: nextActivePbis,
+      activeStories: nextActiveStories,
+    },
+  })
+}
+
 export async function resolveActiveSprint(
   productId: string,
   userId: string,
diff --git a/lib/user-settings.ts b/lib/user-settings.ts
index 5139261..0bcb92f 100644
--- a/lib/user-settings.ts
+++ b/lib/user-settings.ts
@@ -46,6 +46,8 @@ const DevToolsPrefs = z.object({
 const LayoutPrefs = z.object({
   splitPanePositions: z.record(z.string(), z.array(z.number())).optional(),
   activeSprints: z.record(z.string(), z.string().nullable()).optional(),
+  activePbis: z.record(z.string(), z.string().nullable()).optional(),
+  activeStories: z.record(z.string(), z.string().nullable()).optional(),
 }).strict()
 
 const PbiIntent = z.enum(['all', 'none'])