diff --git a/src/components/admin/__tests__/encryption-legacy-badge.test.tsx b/src/components/admin/__tests__/encryption-legacy-badge.test.tsx
index 07c461003..055ac5f63 100644
--- a/src/components/admin/__tests__/encryption-legacy-badge.test.tsx
+++ b/src/components/admin/__tests__/encryption-legacy-badge.test.tsx
@@ -131,6 +131,12 @@ describe("encryption coverage — the per-column table", () => {
     expect(html).not.toContain('data-slot="encryption-column-rows"');
   });
 
+  it("keeps the toggle's aria-controls target in the tree while collapsed", () => {
+    const html = renderCoverage(false);
+    expect(html).toContain('aria-controls="encryption-columns-panel"');
+    expect(html).toMatch(/<div id="encryption-columns-panel" hidden=""/);
+  });
+
   it("lists only columns with rows when opened, with a toggle for all", () => {
     const html = renderCoverage(true);
     expect(html).toContain("User.withRows");
diff --git a/src/components/admin/encryption-section.tsx b/src/components/admin/encryption-section.tsx
index 8879cea70..a3cc9a675 100644
--- a/src/components/admin/encryption-section.tsx
+++ b/src/components/admin/encryption-section.tsx
@@ -410,87 +410,93 @@ export function ColumnCoverage({
               count: withRows.length,
             })}
       </button>
-      {open ? (
-        <div id="encryption-columns-panel" className="space-y-3">
-          {shown.length === 0 ? (
-            <p className="text-muted-foreground text-sm">
-              {t("admin.section.encryption.columnsNoneWithRows")}
-            </p>
-          ) : (
-            /* Focusable, named scroll region: on a phone the table scrolls
+      {/* The panel stays in the tree, empty and hidden, while closed, so
+          the toggle's aria-controls always names an element. */}
+      <div id="encryption-columns-panel" hidden={!open} className="space-y-3">
+        {open ? (
+          <>
+            {shown.length === 0 ? (
+              <p className="text-muted-foreground text-sm">
+                {t("admin.section.encryption.columnsNoneWithRows")}
+              </p>
+            ) : (
+              /* Focusable, named scroll region: on a phone the table scrolls
                sideways, and a keyboard user has to be able to reach it
                (axe scrollable-region-focusable). */
-            <div
-              className="overflow-x-auto"
-              tabIndex={0}
-              role="region"
-              aria-label={t("admin.section.encryption.columnsTitle")}
-            >
-              <table className="w-full text-sm">
-                <thead>
-                  <tr className="text-muted-foreground border-b text-left">
-                    <th className="py-2 pr-3 font-medium">
-                      {t("admin.section.encryption.colColumn")}
-                    </th>
-                    <th className="py-2 pr-3 font-medium">
-                      {t("admin.section.encryption.colTotal")}
-                    </th>
-                    <th className="py-2 pr-3 font-medium">
-                      {t("admin.section.encryption.colActive")}
-                    </th>
-                    <th className="py-2 font-medium">
-                      {t("admin.section.encryption.colStale")}
-                    </th>
-                  </tr>
-                </thead>
-                <tbody data-slot="encryption-column-rows">
-                  {shown.map((c) => {
-                    const active = c.byKeyId[activeKeyId] ?? 0;
-                    const stale = c.total - active;
-                    return (
-                      <tr key={`${c.model}.${c.field}`} className="border-b">
-                        <td className="py-2 pr-3 font-mono text-xs">
-                          {c.model}.{c.field}
-                        </td>
-                        <td className="py-2 pr-3">
-                          {c.total.toLocaleString()}
-                        </td>
-                        <td className="py-2 pr-3">{active.toLocaleString()}</td>
-                        <td className="py-2">
-                          {stale > 0 ? (
-                            <Badge variant="secondary">
-                              {stale.toLocaleString()}
-                            </Badge>
-                          ) : (
-                            <span className="text-muted-foreground">0</span>
-                          )}
-                        </td>
-                      </tr>
-                    );
-                  })}
-                </tbody>
-              </table>
-            </div>
-          )}
-          {withRows.length < columns.length ? (
-            <Button
-              type="button"
-              variant="outline"
-              size="sm"
-              className="min-h-11 sm:min-h-9"
-              onClick={() => setShowAll((prev) => !prev)}
-              aria-pressed={showAll}
-              data-testid="encryption-columns-show-all"
-            >
-              {showAll
-                ? t("admin.section.encryption.columnsShowWithRows")
-                : t("admin.section.encryption.columnsShowAll", {
-                    count: columns.length,
-                  })}
-            </Button>
-          ) : null}
-        </div>
-      ) : null}
+              <div
+                className="overflow-x-auto"
+                tabIndex={0}
+                role="region"
+                aria-label={t("admin.section.encryption.columnsTitle")}
+              >
+                <table className="w-full text-sm">
+                  <thead>
+                    <tr className="text-muted-foreground border-b text-left">
+                      <th className="py-2 pr-3 font-medium">
+                        {t("admin.section.encryption.colColumn")}
+                      </th>
+                      <th className="py-2 pr-3 font-medium">
+                        {t("admin.section.encryption.colTotal")}
+                      </th>
+                      <th className="py-2 pr-3 font-medium">
+                        {t("admin.section.encryption.colActive")}
+                      </th>
+                      <th className="py-2 font-medium">
+                        {t("admin.section.encryption.colStale")}
+                      </th>
+                    </tr>
+                  </thead>
+                  <tbody data-slot="encryption-column-rows">
+                    {shown.map((c) => {
+                      const active = c.byKeyId[activeKeyId] ?? 0;
+                      const stale = c.total - active;
+                      return (
+                        <tr key={`${c.model}.${c.field}`} className="border-b">
+                          <td className="py-2 pr-3 font-mono text-xs">
+                            {c.model}.{c.field}
+                          </td>
+                          <td className="py-2 pr-3">
+                            {c.total.toLocaleString()}
+                          </td>
+                          <td className="py-2 pr-3">
+                            {active.toLocaleString()}
+                          </td>
+                          <td className="py-2">
+                            {stale > 0 ? (
+                              <Badge variant="secondary">
+                                {stale.toLocaleString()}
+                              </Badge>
+                            ) : (
+                              <span className="text-muted-foreground">0</span>
+                            )}
+                          </td>
+                        </tr>
+                      );
+                    })}
+                  </tbody>
+                </table>
+              </div>
+            )}
+            {withRows.length < columns.length ? (
+              <Button
+                type="button"
+                variant="outline"
+                size="sm"
+                className="min-h-11 sm:min-h-9"
+                onClick={() => setShowAll((prev) => !prev)}
+                aria-pressed={showAll}
+                data-testid="encryption-columns-show-all"
+              >
+                {showAll
+                  ? t("admin.section.encryption.columnsShowWithRows")
+                  : t("admin.section.encryption.columnsShowAll", {
+                      count: columns.length,
+                    })}
+              </Button>
+            ) : null}
+          </>
+        ) : null}
+      </div>
     </div>
   );
 }
diff --git a/src/components/settings/__tests__/sources-section-in-use.test.tsx b/src/components/settings/__tests__/sources-section-in-use.test.tsx
index e2b2dbb16..a99f7a2a8 100644
--- a/src/components/settings/__tests__/sources-section-in-use.test.tsx
+++ b/src/components/settings/__tests__/sources-section-in-use.test.tsx
@@ -45,6 +45,15 @@ describe("Settings → Source priority, sources in use", () => {
     expect(html).toContain('aria-expanded="false"');
   });
 
+  it("names an element with every toggle's aria-controls, open or not", () => {
+    const html = render(["WITHINGS", "MANUAL"]);
+    const controls = [...html.matchAll(/aria-controls="([^"]+)"/g)].map(
+      (m) => m[1]!,
+    );
+    expect(controls.length).toBeGreaterThan(1);
+    for (const id of controls) expect(html).toContain(`id="${id}"`);
+  });
+
   it("says so when no source is in use at all", () => {
     expect(render([])).toContain('data-testid="sources-none-in-use"');
   });
diff --git a/src/components/settings/sources-section.tsx b/src/components/settings/sources-section.tsx
index 57df0ca70..69dd2b3ae 100644
--- a/src/components/settings/sources-section.tsx
+++ b/src/components/settings/sources-section.tsx
@@ -420,55 +420,66 @@ export function SourcesSection() {
                       </span>
                     ) : null}
                   </button>
-                  {open ? (
-                    <ul id={panelId} className="space-y-1 px-3 pb-3">
-                      {list.map((source, index) => (
-                        <li
-                          key={`${metric}-${source}`}
-                          className="border-border bg-card flex items-center gap-2 rounded-md border px-2 py-1.5"
-                        >
-                          <span className="text-muted-foreground w-5 text-xs font-medium tabular-nums">
-                            {index + 1}.
-                          </span>
-                          <span className="flex-1 text-sm">
-                            {t(MEASUREMENT_SOURCE_SETTINGS_LABEL_KEYS[source])}
-                          </span>
-                          {/* Up/down sit side by side at every width: two
+                  {/* The list stays in the tree, empty and hidden, while
+                      the group is closed, so the toggle's aria-controls
+                      always names an element. */}
+                  <ul
+                    id={panelId}
+                    hidden={!open}
+                    className="space-y-1 px-3 pb-3"
+                  >
+                    {open
+                      ? list.map((source, index) => (
+                          <li
+                            key={`${metric}-${source}`}
+                            className="border-border bg-card flex items-center gap-2 rounded-md border px-2 py-1.5"
+                          >
+                            <span className="text-muted-foreground w-5 text-xs font-medium tabular-nums">
+                              {index + 1}.
+                            </span>
+                            <span className="flex-1 text-sm">
+                              {t(
+                                MEASUREMENT_SOURCE_SETTINGS_LABEL_KEYS[source],
+                              )}
+                            </span>
+                            {/* Up/down sit side by side at every width: two
                               44 px buttons leave a 390 px row ~170 px for the
                               source name. */}
-                          <div className="flex shrink-0 gap-1 sm:gap-2">
-                            <Button
-                              type="button"
-                              variant="ghost"
-                              size="icon"
-                              className="h-11 w-11"
-                              onClick={() => moveSource(metric, source, -1)}
-                              disabled={index === 0 || saveMutation.isPending}
-                              aria-label={t("settings.sections.sources.moveUp")}
-                            >
-                              <ArrowUp className="h-4 w-4" />
-                            </Button>
-                            <Button
-                              type="button"
-                              variant="ghost"
-                              size="icon"
-                              className="h-11 w-11"
-                              onClick={() => moveSource(metric, source, 1)}
-                              disabled={
-                                index === list.length - 1 ||
-                                saveMutation.isPending
-                              }
-                              aria-label={t(
-                                "settings.sections.sources.moveDown",
-                              )}
-                            >
-                              <ArrowDown className="h-4 w-4" />
-                            </Button>
-                          </div>
-                        </li>
-                      ))}
-                    </ul>
-                  ) : null}
+                            <div className="flex shrink-0 gap-1 sm:gap-2">
+                              <Button
+                                type="button"
+                                variant="ghost"
+                                size="icon"
+                                className="h-11 w-11"
+                                onClick={() => moveSource(metric, source, -1)}
+                                disabled={index === 0 || saveMutation.isPending}
+                                aria-label={t(
+                                  "settings.sections.sources.moveUp",
+                                )}
+                              >
+                                <ArrowUp className="h-4 w-4" />
+                              </Button>
+                              <Button
+                                type="button"
+                                variant="ghost"
+                                size="icon"
+                                className="h-11 w-11"
+                                onClick={() => moveSource(metric, source, 1)}
+                                disabled={
+                                  index === list.length - 1 ||
+                                  saveMutation.isPending
+                                }
+                                aria-label={t(
+                                  "settings.sections.sources.moveDown",
+                                )}
+                              >
+                                <ArrowDown className="h-4 w-4" />
+                              </Button>
+                            </div>
+                          </li>
+                        ))
+                      : null}
+                  </ul>
                 </div>
               );
             })}
@@ -497,46 +508,49 @@ export function SourcesSection() {
                 count: overriddenMetrics.length,
               })}
             </button>
-            {showPerMetric && (
-              <div
-                id="sources-per-metric-panel"
-                role="region"
-                className="bg-background/30 border-border space-y-3 rounded-md border p-3"
-              >
-                <p className="text-muted-foreground text-xs">
-                  {t("settings.sections.sources.perMetricHelp")}
-                </p>
-                {overriddenMetrics.length === 0 ? (
-                  <EmptyState
-                    variant="plain"
-                    size="compact"
-                    title={t("settings.sections.sources.perMetricEmpty")}
-                  />
-                ) : (
-                  <ul className="space-y-2">
-                    {overriddenMetrics.map((metric) => (
-                      <li
-                        key={metric}
-                        className="border-border bg-card flex items-center justify-between gap-3 rounded-md border px-3 py-2"
-                      >
-                        <span className="text-sm">
-                          {t(METRIC_LABEL_KEYS[metric])}
-                        </span>
-                        <Button
-                          type="button"
-                          variant="ghost"
-                          size="sm"
-                          onClick={() => resetMetricToDefault(metric)}
-                          disabled={saveMutation.isPending}
+            <div
+              id="sources-per-metric-panel"
+              role="region"
+              hidden={!showPerMetric}
+              className="bg-background/30 border-border space-y-3 rounded-md border p-3"
+            >
+              {showPerMetric ? (
+                <>
+                  <p className="text-muted-foreground text-xs">
+                    {t("settings.sections.sources.perMetricHelp")}
+                  </p>
+                  {overriddenMetrics.length === 0 ? (
+                    <EmptyState
+                      variant="plain"
+                      size="compact"
+                      title={t("settings.sections.sources.perMetricEmpty")}
+                    />
+                  ) : (
+                    <ul className="space-y-2">
+                      {overriddenMetrics.map((metric) => (
+                        <li
+                          key={metric}
+                          className="border-border bg-card flex items-center justify-between gap-3 rounded-md border px-3 py-2"
                         >
-                          {t("settings.sections.sources.resetMetric")}
-                        </Button>
-                      </li>
-                    ))}
-                  </ul>
-                )}
-              </div>
-            )}
+                          <span className="text-sm">
+                            {t(METRIC_LABEL_KEYS[metric])}
+                          </span>
+                          <Button
+                            type="button"
+                            variant="ghost"
+                            size="sm"
+                            onClick={() => resetMetricToDefault(metric)}
+                            disabled={saveMutation.isPending}
+                          >
+                            {t("settings.sections.sources.resetMetric")}
+                          </Button>
+                        </li>
+                      ))}
+                    </ul>
+                  )}
+                </>
+              ) : null}
+            </div>
           </div>
         )}
 
@@ -563,78 +577,82 @@ export function SourcesSection() {
                 count: deviceTypeOverrideCount,
               })}
             </button>
-            {showDeviceType && (
-              <div
-                id="sources-device-type-panel"
-                role="region"
-                className="bg-background/30 border-border space-y-3 rounded-md border p-3"
-              >
-                <p className="text-muted-foreground text-xs">
-                  {t("settings.sections.sources.deviceTypeHelp")}
-                </p>
-                <div className="flex items-center justify-between">
-                  <span className="text-sm font-medium">
-                    {t("settings.sections.sources.deviceTypeDefault")}
-                  </span>
-                  <Button
-                    type="button"
-                    variant="ghost"
-                    size="sm"
-                    onClick={resetDeviceTypeAxis}
-                    disabled={saveMutation.isPending}
-                  >
-                    <RotateCcw className="h-3 w-3" />
-                    {t("settings.sections.sources.resetDeviceTypes")}
-                  </Button>
-                </div>
-                <ul className="space-y-1">
-                  {(
-                    priority.deviceTypePriority.default ??
-                    DEFAULT_DEVICE_TYPE_PRIORITY
-                  ).map((deviceType, index, list) => (
-                    <li
-                      key={`device-default-${deviceType}-${index}`}
-                      className="border-border bg-card flex items-center gap-2 rounded-md border px-2 py-1.5"
+            <div
+              id="sources-device-type-panel"
+              role="region"
+              hidden={!showDeviceType}
+              className="bg-background/30 border-border space-y-3 rounded-md border p-3"
+            >
+              {showDeviceType ? (
+                <>
+                  <p className="text-muted-foreground text-xs">
+                    {t("settings.sections.sources.deviceTypeHelp")}
+                  </p>
+                  <div className="flex items-center justify-between">
+                    <span className="text-sm font-medium">
+                      {t("settings.sections.sources.deviceTypeDefault")}
+                    </span>
+                    <Button
+                      type="button"
+                      variant="ghost"
+                      size="sm"
+                      onClick={resetDeviceTypeAxis}
+                      disabled={saveMutation.isPending}
                     >
-                      <span className="text-muted-foreground w-5 text-xs font-medium tabular-nums">
-                        {index + 1}.
-                      </span>
-                      <span className="flex-1 text-sm">
-                        {t(DEVICE_TYPE_LABEL_KEYS[deviceType])}
-                      </span>
-                      {/* v1.4.27 R3d MB2 — same stacked-on-mobile shape
+                      <RotateCcw className="h-3 w-3" />
+                      {t("settings.sections.sources.resetDeviceTypes")}
+                    </Button>
+                  </div>
+                  <ul className="space-y-1">
+                    {(
+                      priority.deviceTypePriority.default ??
+                      DEFAULT_DEVICE_TYPE_PRIORITY
+                    ).map((deviceType, index, list) => (
+                      <li
+                        key={`device-default-${deviceType}-${index}`}
+                        className="border-border bg-card flex items-center gap-2 rounded-md border px-2 py-1.5"
+                      >
+                        <span className="text-muted-foreground w-5 text-xs font-medium tabular-nums">
+                          {index + 1}.
+                        </span>
+                        <span className="flex-1 text-sm">
+                          {t(DEVICE_TYPE_LABEL_KEYS[deviceType])}
+                        </span>
+                        {/* v1.4.27 R3d MB2 — same stacked-on-mobile shape
                           as the metric source rows above. */}
-                      <div className="flex flex-col gap-1 sm:flex-row sm:gap-2">
-                        <Button
-                          type="button"
-                          variant="ghost"
-                          size="icon"
-                          className="h-11 w-11"
-                          onClick={() => moveDeviceType(null, index, -1)}
-                          disabled={index === 0 || saveMutation.isPending}
-                          aria-label={t("settings.sections.sources.moveUp")}
-                        >
-                          <ArrowUp className="h-4 w-4" />
-                        </Button>
-                        <Button
-                          type="button"
-                          variant="ghost"
-                          size="icon"
-                          className="h-11 w-11"
-                          onClick={() => moveDeviceType(null, index, 1)}
-                          disabled={
-                            index === list.length - 1 || saveMutation.isPending
-                          }
-                          aria-label={t("settings.sections.sources.moveDown")}
-                        >
-                          <ArrowDown className="h-4 w-4" />
-                        </Button>
-                      </div>
-                    </li>
-                  ))}
-                </ul>
-              </div>
-            )}
+                        <div className="flex flex-col gap-1 sm:flex-row sm:gap-2">
+                          <Button
+                            type="button"
+                            variant="ghost"
+                            size="icon"
+                            className="h-11 w-11"
+                            onClick={() => moveDeviceType(null, index, -1)}
+                            disabled={index === 0 || saveMutation.isPending}
+                            aria-label={t("settings.sections.sources.moveUp")}
+                          >
+                            <ArrowUp className="h-4 w-4" />
+                          </Button>
+                          <Button
+                            type="button"
+                            variant="ghost"
+                            size="icon"
+                            className="h-11 w-11"
+                            onClick={() => moveDeviceType(null, index, 1)}
+                            disabled={
+                              index === list.length - 1 ||
+                              saveMutation.isPending
+                            }
+                            aria-label={t("settings.sections.sources.moveDown")}
+                          >
+                            <ArrowDown className="h-4 w-4" />
+                          </Button>
+                        </div>
+                      </li>
+                    ))}
+                  </ul>
+                </>
+              ) : null}
+            </div>
           </div>
         )}