diff --git a/src/app/api/dashboard/widgets/route.ts b/src/app/api/dashboard/widgets/route.ts
index cb56bb4bc..56f43351a 100644
--- a/src/app/api/dashboard/widgets/route.ts
+++ b/src/app/api/dashboard/widgets/route.ts
@@ -13,27 +13,24 @@ import {
   resolveDashboardLayout,
   serializeDashboardLayout,
   DEFAULT_DASHBOARD_LAYOUT,
+  DASHBOARD_WIDGET_IDS,
   type DashboardLayout,
 } from "@/lib/dashboard-layout";
 import { Prisma } from "@/generated/prisma/client";
 import { z } from "zod/v4";
 import type { NextRequest } from "next/server";
 
-const widgetIdEnum = z.enum([
-  "weight",
-  "bp",
-  "pulse",
-  "bodyFat",
-  "mood",
-  "medications",
-  "sleep",
-  "steps",
-  "glucose",
-  "totalBodyWater",
-  "boneMass",
-  "bpInTarget",
-  "oxygenSaturation",
-]);
+// Single source of truth — every widget id rendered by the Settings →
+// Dashboard UI (`src/components/settings/dashboard-layout-section.tsx`
+// iterates the full layout from `DEFAULT_DASHBOARD_LAYOUT`). Missing
+// one here makes the PUT 422 silently — the toast surfaces "Layout
+// konnte nicht gespeichert werden" — and Marc's tile-toggle looks
+// like it does nothing because the save round-trip never completes.
+// v1.4.16 A5 root-cause: `achievements` was absent from this enum so
+// every save attempted with the achievements widget present (i.e.
+// every save against the default layout) was rejected. We now derive
+// the enum from `DASHBOARD_WIDGET_IDS` so the two lists cannot drift.
+const widgetIdEnum = z.enum(DASHBOARD_WIDGET_IDS);
 
 const layoutSchema = z.object({
   version: z.literal(1),
diff --git a/src/app/page.tsx b/src/app/page.tsx
index bed38dc08..b7d7e67c2 100644
--- a/src/app/page.tsx
+++ b/src/app/page.tsx
@@ -995,28 +995,40 @@ export default function DashboardPage() {
              * makes the scroll feel deliberate rather than arbitrary on
              * touch.
              */}
-            <div
-              // CSS Grid with `auto-fit + minmax(9rem, 1fr)` is the v1.4.4
-              // attempt's flex-strip replacement: every tile gets EXACTLY
-              // the same width (1fr each in the row's track list), the gap
-              // is symmetric, and the strip starts and ends at the same
-              // x-coordinates as the charts below because both inherit the
-              // same parent container. When the row no longer fits a 9rem
-              // floor, the grid wraps to a new row instead of horizontal-
-              // scrolling — Marc tested both and prefers the v1.3-era
-              // wrap behaviour over the one-row scroll for the symmetry
-              // it preserves.
-              className="grid auto-rows-fr [grid-template-columns:repeat(auto-fit,minmax(9rem,1fr))] gap-3 pb-2"
-              data-slot="dashboard-tile-strip"
-              data-tour-id="dashboard-tile-strip"
-              data-tile-count={trendCards.length}
-            >
-              {trendCards.map((entry) => (
-                <div key={entry.id} className="flex">
-                  {entry.node}
-                </div>
-              ))}
-            </div>
+            {/* v1.4.16 Fix A5: hide the strip entirely when the user
+                turned off every tile. Until v1.4.15 the wrapper rendered
+                an empty grid even with zero tiles — visually a thin gap
+                Marc described as "awkward". Charts below still render so
+                the page is not empty; the tile-strip just goes away.
+                The constraint Marc named — "immer die gesamte Spalte
+                breit und immer der gleichen Höhe" — is preserved by the
+                CSS-grid `auto-fit + minmax + auto-rows-fr` track that
+                continues to give every visible tile equal width / equal
+                height for any non-zero count. */}
+            {trendCards.length > 0 && (
+              <div
+                // CSS Grid with `auto-fit + minmax(9rem, 1fr)` is the v1.4.4
+                // attempt's flex-strip replacement: every tile gets EXACTLY
+                // the same width (1fr each in the row's track list), the gap
+                // is symmetric, and the strip starts and ends at the same
+                // x-coordinates as the charts below because both inherit the
+                // same parent container. When the row no longer fits a 9rem
+                // floor, the grid wraps to a new row instead of horizontal-
+                // scrolling — Marc tested both and prefers the v1.3-era
+                // wrap behaviour over the one-row scroll for the symmetry
+                // it preserves.
+                className="grid auto-rows-fr [grid-template-columns:repeat(auto-fit,minmax(9rem,1fr))] gap-3 pb-2"
+                data-slot="dashboard-tile-strip"
+                data-tour-id="dashboard-tile-strip"
+                data-tile-count={trendCards.length}
+              >
+                {trendCards.map((entry) => (
+                  <div key={entry.id} className="flex">
+                    {entry.node}
+                  </div>
+                ))}
+              </div>
+            )}
             {charts.map((entry) => (
               <div key={entry.id} className="space-y-2">
                 {entry.node}
diff --git a/src/lib/__tests__/dashboard-layout.test.ts b/src/lib/__tests__/dashboard-layout.test.ts
index ca37a22c5..1455d7e54 100644
--- a/src/lib/__tests__/dashboard-layout.test.ts
+++ b/src/lib/__tests__/dashboard-layout.test.ts
@@ -116,3 +116,41 @@ describe("serializeDashboardLayout() — tileVisible persistence", () => {
     expect(serialized.widgets.map((w) => w.order)).toEqual([0, 1]);
   });
 });
+
+/**
+ * v1.4.16 Fix A5 — top-tile selector real-fix.
+ *
+ * Marc reported the toggles in Settings → Dashboard didn't filter
+ * the dashboard tile-strip. Root cause: the `widgetIdEnum` Zod schema
+ * in `src/app/api/dashboard/widgets/route.ts` was missing
+ * `achievements` even though the default layout has it. Every PUT
+ * therefore 422'd silently against the achievements widget that the
+ * UI included unconditionally — the server never persisted the toggle
+ * change, so reload showed the old layout.
+ *
+ * The default layout itself is the contract — if a widget is in
+ * `DEFAULT_DASHBOARD_LAYOUT.widgets`, every consumer (settings UI,
+ * dashboard renderer, API schema) must support it. This test pins
+ * the contract by enumerating every widget the default layout
+ * advertises, so a future addition gets caught here before Marc
+ * finds it broken in production.
+ */
+describe("DEFAULT_DASHBOARD_LAYOUT contract", () => {
+  it("includes the achievements widget (v1.4.15 phase-B4 + v1.4.16 A5)", () => {
+    const ids = DEFAULT_DASHBOARD_LAYOUT.widgets.map((w) => w.id);
+    expect(ids).toContain("achievements");
+  });
+
+  it("survives a round-trip through serialize → resolve unchanged", () => {
+    // The API persists `serializeDashboardLayout(parsed.data)` and
+    // reads back via `resolveDashboardLayout(row.dashboardWidgetsJson)`.
+    // A bug in either step (missing widget, wrong order normalization)
+    // would surface here. Marc's regression: the API schema rejected
+    // the layout *before* this round-trip even started.
+    const serialized = serializeDashboardLayout(DEFAULT_DASHBOARD_LAYOUT);
+    const resolved = resolveDashboardLayout(serialized);
+    expect(resolved.widgets.map((w) => w.id).sort()).toEqual(
+      DEFAULT_DASHBOARD_LAYOUT.widgets.map((w) => w.id).sort(),
+    );
+  });
+});
diff --git a/src/lib/dashboard-layout.ts b/src/lib/dashboard-layout.ts
index 0b18c2030..0bb7040b4 100644
--- a/src/lib/dashboard-layout.ts
+++ b/src/lib/dashboard-layout.ts
@@ -5,21 +5,33 @@
  * what the default layout is for new users. Null / missing = default.
  */
 
-export type DashboardWidgetId =
-  | "weight"
-  | "bp"
-  | "pulse"
-  | "bodyFat"
-  | "mood"
-  | "medications"
-  | "sleep"
-  | "steps"
-  | "glucose"
-  | "totalBodyWater"
-  | "boneMass"
-  | "bpInTarget"
-  | "oxygenSaturation"
-  | "achievements";
+/**
+ * Every widget the dashboard layout knows about. The order of
+ * entries here is irrelevant — `DEFAULT_DASHBOARD_LAYOUT.widgets[].order`
+ * is the visual order. This array is exported so the API Zod
+ * `widgetIdEnum` (in `src/app/api/dashboard/widgets/route.ts`) can be
+ * built from a single source of truth — v1.4.16 Fix A5 root cause was
+ * the enum drifting away from the default-layout list, which silently
+ * 422'd every save.
+ */
+export const DASHBOARD_WIDGET_IDS = [
+  "weight",
+  "bp",
+  "pulse",
+  "bodyFat",
+  "mood",
+  "medications",
+  "sleep",
+  "steps",
+  "glucose",
+  "totalBodyWater",
+  "boneMass",
+  "bpInTarget",
+  "oxygenSaturation",
+  "achievements",
+] as const;
+
+export type DashboardWidgetId = (typeof DASHBOARD_WIDGET_IDS)[number];
 
 export interface DashboardWidgetConfig {
   id: DashboardWidgetId;