diff --git a/frontend/packages/dashboard/src/app.js b/frontend/packages/dashboard/src/app.js
index 231b0e44..7056579c 100644
--- a/frontend/packages/dashboard/src/app.js
+++ b/frontend/packages/dashboard/src/app.js
@@ -41,28 +41,6 @@ window.marked = marked;
 
   // Helpers ($, el, esc, form, fmtAgeSecs) moved to ./common.js (#406).
 
-  // #464 — atomic-swap render helper. Each managed section's render
-  // function used to do `root.innerHTML = ''; root.append(...);` in
-  // sequence; even though both operations sit in the same JS turn,
-  // operators could still see a "blink" on every poll cycle because
-  // (a) on async paths the await yield gave the browser a paint
-  // opportunity, and (b) complex builds with many `el()` allocations
-  // can blow the browser's per-task budget enough for layout to flash
-  // empty before the new children land.
-  //
-  // The fix: build the new content off-DOM into a `DocumentFragment`,
-  // then move it into the live root in a single `replaceChildren`
-  // call. The browser never sees an intermediate empty state. Builder
-  // callbacks receive the fragment as their `root` argument, so each
-  // renderer's existing `root.append(...)` code carries over with
-  // zero internal changes. Early-return inside the builder is fine —
-  // the commit still happens with whatever the builder appended.
-  function paintAtomic(liveRoot, build) {
-    const buf = document.createDocumentFragment();
-    build(buf);
-    liveRoot.replaceChildren(buf);
-  }
-
   // Side panel singleton (Panel) moved to ./common.js (#406).
 
   // Path linkification + file-preview side panel (openFilePanel,
@@ -1849,92 +1827,89 @@ window.marked = marked;
   // agents themselves and the operator already sees them next time
   // they interact with the page.
   async function refreshReminders() {
-    const liveRoot = $('reminders-section');
-    if (!liveRoot) return;
+    const root = $('reminders-section');
+    if (!root) return;
     try {
       const resp = await fetch('/api/reminders');
       if (!resp.ok) {
-        paintAtomic(liveRoot, (root) => {
-          root.append(el('p', { class: 'empty' }, 'reminders unavailable: http ' + resp.status));
-        });
+        root.innerHTML = '';
+        root.append(el('p', { class: 'empty' }, 'reminders unavailable: http ' + resp.status));
         return;
       }
       const rows = await resp.json();
       renderReminders(rows);
     } catch (err) {
-      paintAtomic(liveRoot, (root) => {
-        root.append(el('p', { class: 'empty' }, 'reminders fetch failed: ' + err));
-      });
+      root.innerHTML = '';
+      root.append(el('p', { class: 'empty' }, 'reminders fetch failed: ' + err));
     }
   }
   function renderReminders(rows) {
-    const liveRoot = $('reminders-section');
-    if (!liveRoot) return;
-    paintAtomic(liveRoot, (root) => {
-      if (!rows.length) {
-        root.append(el('p', { class: 'empty' }, 'no queued reminders'));
-        return;
+    const root = $('reminders-section');
+    if (!root) return;
+    root.innerHTML = '';
+    if (!rows.length) {
+      root.append(el('p', { class: 'empty' }, 'no queued reminders'));
+      return;
+    }
+    const ul = el('ul', { class: 'reminders' });
+    for (const r of rows) {
+      const failed = (r.attempt_count || 0) > 0;
+      const li = el('li', { class: 'reminder-row' + (failed ? ' reminder-failed' : '') });
+      const dueIn = r.due_at - Math.floor(Date.now() / 1000);
+      const dueLabel = dueIn <= 0
+        ? `overdue ${fmtAgo(r.due_at)}`
+        : `in ${fmtDuration(dueIn)}`;
+      const head = el('div', { class: 'reminder-head' },
+        el('span', { class: 'agent' }, r.agent), ' ',
+        el('span', { class: 'meta', title: new Date(r.due_at * 1000).toISOString() }, dueLabel),
+        ' ',
+        el('span', { class: 'meta' }, `· id ${r.id}`),
+      );
+      if (r.file_path) {
+        head.append(' ', el('span', { class: 'meta' }, '· payload → '));
+        appendLinkified(head, r.file_path);
       }
-      const ul = el('ul', { class: 'reminders' });
-      for (const r of rows) {
-        const failed = (r.attempt_count || 0) > 0;
-        const li = el('li', { class: 'reminder-row' + (failed ? ' reminder-failed' : '') });
-        const dueIn = r.due_at - Math.floor(Date.now() / 1000);
-        const dueLabel = dueIn <= 0
-          ? `overdue ${fmtAgo(r.due_at)}`
-          : `in ${fmtDuration(dueIn)}`;
-        const head = el('div', { class: 'reminder-head' },
-          el('span', { class: 'agent' }, r.agent), ' ',
-          el('span', { class: 'meta', title: new Date(r.due_at * 1000).toISOString() }, dueLabel),
-          ' ',
-          el('span', { class: 'meta' }, `· id ${r.id}`),
-        );
-        if (r.file_path) {
-          head.append(' ', el('span', { class: 'meta' }, '· payload → '));
-          appendLinkified(head, r.file_path);
-        }
-        if (failed) {
-          head.append(' ', el('span',
-            {
-              class: 'badge badge-warn',
-              title: 'consecutive failed delivery attempts (capped at 5; over the cap the scheduler stops retrying until you click R3TRY or cancel)',
-            },
-            `⚠ ${r.attempt_count} failed`));
-        }
-        const body = el('div', { class: 'reminder-body' });
-        appendLinkified(body, r.message);
-        li.append(head, body);
-        if (r.last_error) {
-          li.append(el('div', { class: 'reminder-error' },
-            el('span', { class: 'msg-sep' }, 'error: '),
-            r.last_error,
-          ));
-        }
-        const actions = el('div', { class: 'reminder-actions' });
-        if (failed) {
-          // Retry resets the failure counters so the scheduler picks
-          // the row up again on its next 5s tick. No data-no-refresh
-          // — the resulting refreshState re-fires refreshReminders.
-          const retryForm = el('form', {
-            method: 'POST', action: '/retry-reminder/' + r.id,
-            class: 'inline', 'data-async': '',
-          });
-          retryForm.append(el('button',
-            { type: 'submit', class: 'btn btn-restart' }, '↻ R3TRY'));
-          actions.append(retryForm);
-        }
-        const cancelForm = el('form', {
-          method: 'POST', action: '/cancel-reminder/' + r.id,
+      if (failed) {
+        head.append(' ', el('span',
+          {
+            class: 'badge badge-warn',
+            title: 'consecutive failed delivery attempts (capped at 5; over the cap the scheduler stops retrying until you click R3TRY or cancel)',
+          },
+          `⚠ ${r.attempt_count} failed`));
+      }
+      const body = el('div', { class: 'reminder-body' });
+      appendLinkified(body, r.message);
+      li.append(head, body);
+      if (r.last_error) {
+        li.append(el('div', { class: 'reminder-error' },
+          el('span', { class: 'msg-sep' }, 'error: '),
+          r.last_error,
+        ));
+      }
+      const actions = el('div', { class: 'reminder-actions' });
+      if (failed) {
+        // Retry resets the failure counters so the scheduler picks
+        // the row up again on its next 5s tick. No data-no-refresh
+        // — the resulting refreshState re-fires refreshReminders.
+        const retryForm = el('form', {
+          method: 'POST', action: '/retry-reminder/' + r.id,
           class: 'inline', 'data-async': '',
-          'data-confirm': `cancel reminder ${r.id} for ${r.agent}? this drops the queued delivery; no undo.`,
         });
-        cancelForm.append(el('button', { type: 'submit', class: 'btn btn-deny' }, '✗ C4NC3L'));
-        actions.append(cancelForm);
-        li.append(actions);
-        ul.append(li);
+        retryForm.append(el('button',
+          { type: 'submit', class: 'btn btn-restart' }, '↻ R3TRY'));
+        actions.append(retryForm);
       }
-      root.append(ul);
-    });
+      const cancelForm = el('form', {
+        method: 'POST', action: '/cancel-reminder/' + r.id,
+        class: 'inline', 'data-async': '',
+        'data-confirm': `cancel reminder ${r.id} for ${r.agent}? this drops the queued delivery; no undo.`,
+      });
+      cancelForm.append(el('button', { type: 'submit', class: 'btn btn-deny' }, '✗ C4NC3L'));
+      actions.append(cancelForm);
+      li.append(actions);
+      ul.append(li);
+    }
+    root.append(ul);
   }
   function fmtDuration(secs) {
     if (secs < 60) return secs + 's';
@@ -1964,16 +1939,14 @@ window.marked = marked;
     try {
       const resp = await fetch('/api/schedules');
       if (!resp.ok) {
-        paintAtomic(listRoot, (root) => {
-          root.append(el('p', { class: 'empty' }, 'schedules unavailable: http ' + resp.status));
-        });
+        listRoot.innerHTML = '';
+        listRoot.append(el('p', { class: 'empty' }, 'schedules unavailable: http ' + resp.status));
         return;
       }
       schedulesState = await resp.json();
     } catch (err) {
-      paintAtomic(listRoot, (root) => {
-        root.append(el('p', { class: 'empty' }, 'schedules fetch failed: ' + err));
-      });
+      listRoot.innerHTML = '';
+      listRoot.append(el('p', { class: 'empty' }, 'schedules fetch failed: ' + err));
       return;
     }
     renderScheduleNewForm();
@@ -2090,15 +2063,13 @@ window.marked = marked;
   }
 
   function renderScheduleNewForm() {
-    const liveRoot = $('schedule-new-section');
-    if (!liveRoot) return;
+    const root = $('schedule-new-section');
+    if (!root) return;
     // Preserve any field the operator was mid-typing in by reading
     // current values before we re-render. Only `body` + `description`
     // are big enough to feel — the others are toggle/datetime/number.
-    // Read from the live root BEFORE the swap so we see current
-    // values (the fragment we build into is fresh).
-    const carry = readScheduleFormCarry(liveRoot);
-    paintAtomic(liveRoot, (root) => {
+    const carry = readScheduleFormCarry(root);
+    root.innerHTML = '';
 
     // Targets multi-select pulls from the live containers list. The
     // backend accepts any string (forward-compat for richer recipients),
@@ -2194,7 +2165,6 @@ window.marked = marked;
     form_.append(actions);
 
     root.append(form_);
-    });  // paintAtomic
   }
   function readScheduleFormCarry(root) {
     return {
@@ -2279,24 +2249,23 @@ window.marked = marked;
     }
   }
   function renderSchedulesList() {
-    const liveRoot = $('schedules-section');
-    if (!liveRoot) return;
-    paintAtomic(liveRoot, (root) => {
-      if (!schedulesState.length) {
-        root.append(el('p', { class: 'empty' }, 'no schedules queued'));
-        return;
-      }
-      const ul = el('ul', { class: 'schedules' });
-      // Active schedules first (still firing), then cancelled tail.
-      const sorted = schedulesState.slice().sort((a, b) => {
-        const aDone = a.cancelled_at_unix ? 1 : 0;
-        const bDone = b.cancelled_at_unix ? 1 : 0;
-        if (aDone !== bDone) return aDone - bDone;
-        return a.next_fire_at_unix - b.next_fire_at_unix;
-      });
-      for (const s of sorted) ul.append(renderScheduleCard(s));
-      root.append(ul);
+    const root = $('schedules-section');
+    if (!root) return;
+    root.innerHTML = '';
+    if (!schedulesState.length) {
+      root.append(el('p', { class: 'empty' }, 'no schedules queued'));
+      return;
+    }
+    const ul = el('ul', { class: 'schedules' });
+    // Active schedules first (still firing), then cancelled tail.
+    const sorted = schedulesState.slice().sort((a, b) => {
+      const aDone = a.cancelled_at_unix ? 1 : 0;
+      const bDone = b.cancelled_at_unix ? 1 : 0;
+      if (aDone !== bDone) return aDone - bDone;
+      return a.next_fire_at_unix - b.next_fire_at_unix;
     });
+    for (const s of sorted) ul.append(renderScheduleCard(s));
+    root.append(ul);
   }
   function renderScheduleCard(s) {
     const cancelled = !!s.cancelled_at_unix;