diff --git a/data/page_status.json b/data/page_status.json
index b81fdb8..6d112a2 100644
--- a/data/page_status.json
+++ b/data/page_status.json
@@ -23,7 +23,7 @@
       "route": "/hold-history",
       "name": "Hold 歷史績效",
       "status": "dev",
-      "drawer_id": "reports",
+      "drawer_id": "drawer-2",
       "order": 3
     },
     {
@@ -40,7 +40,7 @@
       "route": "/resource-history",
       "name": "設備歷史績效",
       "status": "released",
-      "drawer_id": "reports",
+      "drawer_id": "drawer-2",
       "order": 5
     },
     {
@@ -75,14 +75,14 @@
       "route": "/job-query",
       "name": "設備維修查詢",
       "status": "released",
-      "drawer_id": "queries",
+      "drawer_id": "drawer",
       "order": 3
     },
     {
       "route": "/query-tool",
       "name": "批次追蹤工具",
-      "status": "released",
-      "drawer_id": "queries",
+      "status": "dev",
+      "drawer_id": "dev-tools",
       "order": 4
     },
     {
@@ -128,12 +128,6 @@
       "order": 1,
       "admin_only": false
     },
-    {
-      "id": "queries",
-      "name": "查詢類",
-      "order": 3,
-      "admin_only": false
-    },
     {
       "id": "dev-tools",
       "name": "開發工具",
@@ -143,6 +137,12 @@
     {
       "id": "drawer",
       "name": "查詢工具",
+      "order": 3,
+      "admin_only": false
+    },
+    {
+      "id": "drawer-2",
+      "name": "歷史報表",
       "order": 2,
       "admin_only": false
     }
diff --git a/frontend/src/job-query/main.js b/frontend/src/job-query/main.js
index 943c612..869fab8 100644
--- a/frontend/src/job-query/main.js
+++ b/frontend/src/job-query/main.js
@@ -63,14 +63,14 @@ function renderTxnCell(txn, apiKey) {
             try {
                 const data = await MesApi.get('/api/job-query/resources');
                 if (data.error) {
-                    document.getElementById('equipmentList').innerHTML = `<div class="error">${data.error}</div>`;
+                    document.getElementById('equipmentList').innerHTML = `<div class="error">${escapeHtml(data.error)}</div>`;
                     return;
                 }
 
                 allEquipments = data.data;
                 renderEquipmentList(allEquipments);
             } catch (error) {
-                document.getElementById('equipmentList').innerHTML = `<div class="error">載入失敗: ${error.message}</div>`;
+                document.getElementById('equipmentList').innerHTML = `<div class="error">載入失敗: ${escapeHtml(error.message)}</div>`;
             }
         }
 
@@ -264,7 +264,7 @@ function renderTxnCell(txn, apiKey) {
                 });
 
                 if (data.error) {
-                    resultSection.innerHTML = `<div class="error">${data.error}</div>`;
+                    resultSection.innerHTML = `<div class="error">${escapeHtml(data.error)}</div>`;
                     return;
                 }
 
@@ -275,7 +275,7 @@ function renderTxnCell(txn, apiKey) {
                 document.getElementById('exportBtn').disabled = jobsData.length === 0;
 
             } catch (error) {
-                resultSection.innerHTML = `<div class="error">查詢失敗: ${error.message}</div>`;
+                resultSection.innerHTML = `<div class="error">查詢失敗: ${escapeHtml(error.message)}</div>`;
             } finally {
                 document.getElementById('queryBtn').disabled = false;
             }
@@ -346,11 +346,13 @@ function renderTxnCell(txn, apiKey) {
 
             resultSection.innerHTML = html;
 
-            // Load expanded histories
+            // Load expanded histories in batches to avoid thundering herd
+            const pendingLoads = [];
             expandedJobs.forEach(jobId => {
                 const idx = jobsData.findIndex(j => j.JOBID === jobId);
-                if (idx >= 0) loadJobHistory(jobId, idx);
+                if (idx >= 0) pendingLoads.push({ jobId, idx });
             });
+            void loadHistoriesBatched(pendingLoads);
         }
 
         // Toggle job history
@@ -382,7 +384,7 @@ function renderTxnCell(txn, apiKey) {
                 const data = await MesApi.get(`/api/job-query/txn/${jobId}`);
 
                 if (data.error) {
-                    container.innerHTML = `<div class="error" style="margin: 10px 20px;">${data.error}</div>`;
+                    container.innerHTML = `<div class="error" style="margin: 10px 20px;">${escapeHtml(data.error)}</div>`;
                     return;
                 }
 
@@ -417,7 +419,16 @@ function renderTxnCell(txn, apiKey) {
                 container.innerHTML = html;
 
             } catch (error) {
-                container.innerHTML = `<div class="error" style="margin: 10px 20px;">載入失敗: ${error.message}</div>`;
+                container.innerHTML = `<div class="error" style="margin: 10px 20px;">載入失敗: ${escapeHtml(error.message)}</div>`;
+            }
+        }
+
+        // Load multiple job histories with concurrency limit
+        const BATCH_CONCURRENCY = 5;
+        async function loadHistoriesBatched(items) {
+            for (let i = 0; i < items.length; i += BATCH_CONCURRENCY) {
+                const batch = items.slice(i, i + BATCH_CONCURRENCY);
+                await Promise.all(batch.map(({ jobId, idx }) => loadJobHistory(jobId, idx)));
             }
         }
 
diff --git a/frontend/src/portal/main.js b/frontend/src/portal/main.js
index d9d2f9c..86072db 100644
--- a/frontend/src/portal/main.js
+++ b/frontend/src/portal/main.js
@@ -29,7 +29,17 @@ import './portal.css';
 
   function activateTab(targetId, toolSrc) {
     sidebarItems.forEach((item) => item.classList.remove('active'));
-    frames.forEach((frame) => frame.classList.remove('active'));
+
+    // Unload inactive iframes to free memory and stop their timers
+    frames.forEach((frame) => {
+      if (frame.classList.contains('active') && frame.id !== targetId) {
+        if (frame.src) {
+          frame.dataset.src = frame.src;
+        }
+        frame.removeAttribute('src');
+      }
+      frame.classList.remove('active');
+    });
 
     const activeItems = document.querySelectorAll(`.sidebar-item[data-target="${targetId}"]`);
     activeItems.forEach((item) => {
diff --git a/frontend/src/qc-gate/composables/useQcGateData.js b/frontend/src/qc-gate/composables/useQcGateData.js
index 8a0c7a3..b3eaff1 100644
--- a/frontend/src/qc-gate/composables/useQcGateData.js
+++ b/frontend/src/qc-gate/composables/useQcGateData.js
@@ -3,6 +3,12 @@ import { computed, onBeforeUnmount, onMounted, ref } from 'vue';
 import { apiGet } from '../../core/api.js';
 
 const REFRESH_INTERVAL_MS = 10 * 60 * 1000;
+const JITTER_FACTOR = 0.15;
+
+function jitteredInterval(baseMs) {
+  const jitter = baseMs * JITTER_FACTOR * (2 * Math.random() - 1);
+  return Math.max(1000, Math.round(baseMs + jitter));
+}
 const API_TIMEOUT_MS = 60000;
 const BUCKET_KEYS = ['lt_6h', '6h_12h', '12h_24h', 'gt_24h'];
 
@@ -106,18 +112,23 @@ export function useQcGateData() {
 
   const stopAutoRefresh = () => {
     if (refreshTimer) {
-      clearInterval(refreshTimer);
+      clearTimeout(refreshTimer);
       refreshTimer = null;
     }
   };
 
-  const startAutoRefresh = () => {
+  const scheduleNextRefresh = () => {
     stopAutoRefresh();
-    refreshTimer = setInterval(() => {
+    refreshTimer = setTimeout(() => {
       if (!document.hidden) {
         void fetchData({ background: true });
       }
-    }, REFRESH_INTERVAL_MS);
+      scheduleNextRefresh();
+    }, jitteredInterval(REFRESH_INTERVAL_MS));
+  };
+
+  const startAutoRefresh = () => {
+    scheduleNextRefresh();
   };
 
   const resetAutoRefresh = () => {
diff --git a/frontend/src/resource-history/App.vue b/frontend/src/resource-history/App.vue
index 658b684..65fb6d4 100644
--- a/frontend/src/resource-history/App.vue
+++ b/frontend/src/resource-history/App.vue
@@ -1,5 +1,5 @@
 <script setup>
-import { computed, reactive, ref } from 'vue';
+import { computed, onMounted, reactive, ref } from 'vue';
 
 import { apiGet, ensureMesApiAvailable } from '../core/api.js';
 import { buildResourceKpiFromHours } from '../core/compute.js';
@@ -306,7 +306,9 @@ async function initPage() {
   await executeQuery();
 }
 
-void initPage();
+onMounted(() => {
+  void initPage();
+});
 </script>
 
 <template>
diff --git a/frontend/src/resource-status/App.vue b/frontend/src/resource-status/App.vue
index e614d16..99c31b2 100644
--- a/frontend/src/resource-status/App.vue
+++ b/frontend/src/resource-status/App.vue
@@ -1,5 +1,5 @@
 <script setup>
-import { computed, reactive, ref } from 'vue';
+import { computed, onMounted, reactive, ref } from 'vue';
 
 import { apiGet, ensureMesApiAvailable } from '../core/api.js';
 import { useAutoRefresh } from '../wip-shared/composables/useAutoRefresh.js';
@@ -430,7 +430,9 @@ async function initPage() {
   await loadData(true);
 }
 
-void initPage();
+onMounted(() => {
+  void initPage();
+});
 </script>
 
 <template>
diff --git a/frontend/src/wip-overview/App.vue b/frontend/src/wip-overview/App.vue
index d80104b..cf95c07 100644
--- a/frontend/src/wip-overview/App.vue
+++ b/frontend/src/wip-overview/App.vue
@@ -1,5 +1,5 @@
 <script setup>
-import { computed, reactive, ref } from 'vue';
+import { computed, onMounted, reactive, ref } from 'vue';
 
 import { apiGet } from '../core/api.js';
 import {
@@ -267,7 +267,9 @@ async function initializePage() {
   await loadAllData(true);
 }
 
-void initializePage();
+onMounted(() => {
+  void initializePage();
+});
 </script>
 
 <template>
diff --git a/frontend/src/wip-shared/composables/useAutoRefresh.js b/frontend/src/wip-shared/composables/useAutoRefresh.js
index be53e74..ad1c667 100644
--- a/frontend/src/wip-shared/composables/useAutoRefresh.js
+++ b/frontend/src/wip-shared/composables/useAutoRefresh.js
@@ -1,6 +1,12 @@
 import { onBeforeUnmount, onMounted } from 'vue';
 
 const DEFAULT_REFRESH_INTERVAL_MS = 10 * 60 * 1000;
+const JITTER_FACTOR = 0.15; // ±15% random jitter to prevent synchronized requests
+
+function jitteredInterval(baseMs) {
+  const jitter = baseMs * JITTER_FACTOR * (2 * Math.random() - 1);
+  return Math.max(1000, Math.round(baseMs + jitter));
+}
 
 export function useAutoRefresh({
   onRefresh,
@@ -14,18 +20,23 @@ export function useAutoRefresh({
 
   function stopAutoRefresh() {
     if (refreshTimer) {
-      clearInterval(refreshTimer);
+      clearTimeout(refreshTimer);
       refreshTimer = null;
     }
   }
 
-  function startAutoRefresh() {
+  function scheduleNextRefresh() {
     stopAutoRefresh();
-    refreshTimer = setInterval(() => {
+    refreshTimer = setTimeout(() => {
       if (!document.hidden) {
         void onRefresh?.();
       }
-    }, intervalMs);
+      scheduleNextRefresh();
+    }, jitteredInterval(intervalMs));
+  }
+
+  function startAutoRefresh() {
+    scheduleNextRefresh();
   }
 
   function resetAutoRefresh() {
diff --git a/src/mes_dashboard/routes/auth_routes.py b/src/mes_dashboard/routes/auth_routes.py
index 5fe883e..527d9d3 100644
--- a/src/mes_dashboard/routes/auth_routes.py
+++ b/src/mes_dashboard/routes/auth_routes.py
@@ -3,17 +3,17 @@
 
 from __future__ import annotations
 
-import logging
-import time
-from collections import defaultdict
-from datetime import datetime
-from threading import Lock
-from urllib.parse import urlparse
+import logging
+import time
+from collections import defaultdict
+from datetime import datetime
+from threading import Lock
+from urllib.parse import urlparse
 
-from flask import Blueprint, flash, redirect, render_template, request, session, url_for
-
-from mes_dashboard.core.csrf import rotate_csrf_token
-from mes_dashboard.services.auth_service import authenticate, is_admin
+from flask import Blueprint, flash, redirect, render_template, request, session, url_for
+
+from mes_dashboard.core.csrf import rotate_csrf_token
+from mes_dashboard.services.auth_service import authenticate, is_admin
 
 logger = logging.getLogger('mes_dashboard.auth_routes')
 auth_bp = Blueprint("auth", __name__, url_prefix="/admin")
@@ -22,63 +22,100 @@ auth_bp = Blueprint("auth", __name__, url_prefix="/admin")
 # ============================================================
 # Rate Limiting for Login Endpoint
 # ============================================================
-# Simple in-memory rate limiter to prevent brute force attacks
+# Redis-backed rate limiter (cross-worker) with in-memory fallback.
 # Configuration: max 5 attempts per IP per 5 minutes
 
 _rate_limit_lock = Lock()
 _login_attempts: dict = defaultdict(list)  # IP -> list of timestamps
-RATE_LIMIT_MAX_ATTEMPTS = 5
-RATE_LIMIT_WINDOW_SECONDS = 300  # 5 minutes
-
-
-def _sanitize_next_url(next_url: str | None) -> str:
-    """Return a safe post-login redirect URL limited to local paths."""
-    fallback = url_for("portal_index")
-    if not next_url:
-        return fallback
-
-    parsed = urlparse(next_url)
-    if parsed.scheme or parsed.netloc:
-        logger.warning("Blocked external next redirect: %s", next_url)
-        return fallback
-
-    if not next_url.startswith("/") or next_url.startswith("//"):
-        return fallback
-
-    return next_url
+_last_cleanup = time.time()
+RATE_LIMIT_MAX_ATTEMPTS = 5
+RATE_LIMIT_WINDOW_SECONDS = 300  # 5 minutes
+_CLEANUP_INTERVAL = 600  # Sweep stale entries every 10 minutes
+_REDIS_LOGIN_KEY_PREFIX = "mes:login_attempts:"
+
+
+def _get_redis():
+    """Get Redis client if available."""
+    try:
+        from mes_dashboard.core.redis_client import get_redis_client
+        return get_redis_client()
+    except Exception:
+        return None
+
+
+def _sanitize_next_url(next_url: str | None) -> str:
+    """Return a safe post-login redirect URL limited to local paths."""
+    fallback = url_for("portal_index")
+    if not next_url:
+        return fallback
+
+    parsed = urlparse(next_url)
+    if parsed.scheme or parsed.netloc:
+        logger.warning("Blocked external next redirect: %s", next_url)
+        return fallback
+
+    if not next_url.startswith("/") or next_url.startswith("//"):
+        return fallback
+
+    return next_url
+
+
+def _cleanup_stale_entries() -> None:
+    """Remove stale IP entries from the in-memory rate limiter."""
+    global _last_cleanup
+    now = time.time()
+    if now - _last_cleanup < _CLEANUP_INTERVAL:
+        return
+    _last_cleanup = now
+    window_start = now - RATE_LIMIT_WINDOW_SECONDS
+    stale_ips = [
+        ip for ip, timestamps in _login_attempts.items()
+        if not timestamps or timestamps[-1] <= window_start
+    ]
+    for ip in stale_ips:
+        del _login_attempts[ip]
 
 
 def _is_rate_limited(ip: str) -> bool:
     """Check if an IP address is rate limited.
 
-    Args:
-        ip: Client IP address.
-
-    Returns:
-        True if rate limited, False otherwise.
+    Uses Redis when available for cross-worker consistency,
+    falls back to in-memory dict otherwise.
     """
+    redis_client = _get_redis()
+    if redis_client:
+        try:
+            key = f"{_REDIS_LOGIN_KEY_PREFIX}{ip}"
+            count = redis_client.get(key)
+            return int(count or 0) >= RATE_LIMIT_MAX_ATTEMPTS
+        except Exception:
+            pass  # Fall through to in-memory
+
     current_time = time.time()
     window_start = current_time - RATE_LIMIT_WINDOW_SECONDS
 
     with _rate_limit_lock:
-        # Clean up old attempts
+        _cleanup_stale_entries()
         _login_attempts[ip] = [
             ts for ts in _login_attempts[ip] if ts > window_start
         ]
-
-        # Check if limit exceeded
-        if len(_login_attempts[ip]) >= RATE_LIMIT_MAX_ATTEMPTS:
-            return True
-
-        return False
+        return len(_login_attempts[ip]) >= RATE_LIMIT_MAX_ATTEMPTS
 
 
 def _record_login_attempt(ip: str) -> None:
-    """Record a login attempt for rate limiting.
+    """Record a login attempt for rate limiting."""
+    redis_client = _get_redis()
+    if redis_client:
+        try:
+            key = f"{_REDIS_LOGIN_KEY_PREFIX}{ip}"
+            pipe = redis_client.pipeline()
+            pipe.incr(key)
+            pipe.expire(key, RATE_LIMIT_WINDOW_SECONDS)
+            pipe.execute()
+            return
+        except Exception:
+            pass  # Fall through to in-memory
 
-    Args:
-        ip: Client IP address.
-    """
     with _rate_limit_lock:
         _login_attempts[ip].append(time.time())
 
@@ -108,27 +145,27 @@ def login():
             user = authenticate(username, password)
             if user is None:
                 error = "帳號或密碼錯誤"
-            elif not is_admin(user):
-                error = "您不是管理員，無法登入後台"
-            else:
-                # Login successful
-                session.clear()
-                session["admin"] = {
-                    "username": user.get("username"),
-                    "displayName": user.get("displayName"),
-                    "mail": user.get("mail"),
-                    "department": user.get("department"),
-                    "login_time": datetime.now().isoformat(),
-                }
-                rotate_csrf_token()
-                next_url = _sanitize_next_url(request.args.get("next"))
-                return redirect(next_url)
+            elif not is_admin(user):
+                error = "您不是管理員，無法登入後台"
+            else:
+                # Login successful
+                session.clear()
+                session["admin"] = {
+                    "username": user.get("username"),
+                    "displayName": user.get("displayName"),
+                    "mail": user.get("mail"),
+                    "department": user.get("department"),
+                    "login_time": datetime.now().isoformat(),
+                }
+                rotate_csrf_token()
+                next_url = _sanitize_next_url(request.args.get("next"))
+                return redirect(next_url)
 
     return render_template("login.html", error=error)
 
 
 @auth_bp.route("/logout")
-def logout():
-    """Admin logout."""
-    session.clear()
-    return redirect(url_for("portal_index"))
+def logout():
+    """Admin logout."""
+    session.clear()
+    return redirect(url_for("portal_index"))
diff --git a/src/mes_dashboard/routes/job_query_routes.py b/src/mes_dashboard/routes/job_query_routes.py
index 313cf2d..fd300c4 100644
--- a/src/mes_dashboard/routes/job_query_routes.py
+++ b/src/mes_dashboard/routes/job_query_routes.py
@@ -1,16 +1,17 @@
 # -*- coding: utf-8 -*-
-"""Job Query API routes.
+"""Job Query API routes.
 
 Contains Flask Blueprint for maintenance job query endpoints:
 - Job list query by resources
 - Job transaction history detail
 - CSV export with full history
-"""
-
-import logging
-
-from flask import Blueprint, jsonify, request, Response, render_template
+"""
 
+import logging
+
+from flask import Blueprint, jsonify, request, Response, render_template
+
+from mes_dashboard.core.rate_limit import configured_rate_limit
 from mes_dashboard.services.job_query_service import (
     get_jobs_by_resources,
     get_job_txn_history,
@@ -18,9 +19,27 @@ from mes_dashboard.services.job_query_service import (
     validate_date_range,
 )
 
-# Create Blueprint
-job_query_bp = Blueprint('job_query', __name__)
-logger = logging.getLogger('mes_dashboard.job_query_routes')
+# Create Blueprint
+job_query_bp = Blueprint('job_query', __name__)
+logger = logging.getLogger('mes_dashboard.job_query_routes')
+
+MAX_RESOURCE_IDS = 50
+
+_JOB_QUERY_RATE_LIMIT = configured_rate_limit(
+    bucket="job-query",
+    max_attempts_env="JOB_QUERY_RATE_LIMIT_MAX_REQUESTS",
+    window_seconds_env="JOB_QUERY_RATE_LIMIT_WINDOW_SECONDS",
+    default_max_attempts=60,
+    default_window_seconds=60,
+)
+
+_JOB_EXPORT_RATE_LIMIT = configured_rate_limit(
+    bucket="job-export",
+    max_attempts_env="JOB_EXPORT_RATE_LIMIT_MAX_REQUESTS",
+    window_seconds_env="JOB_EXPORT_RATE_LIMIT_WINDOW_SECONDS",
+    default_max_attempts=10,
+    default_window_seconds=60,
+)
 
 
 # ============================================================
@@ -68,12 +87,13 @@ def get_resources():
             'total': len(data)
         })
 
-    except Exception as exc:
-        logger.exception("Failed to load job-query resources: %s", exc)
-        return jsonify({'error': '服務暫時無法使用'}), 500
+    except Exception as exc:
+        logger.exception("Failed to load job-query resources: %s", exc)
+        return jsonify({'error': '服務暫時無法使用'}), 500
 
 
 @job_query_bp.route('/api/job-query/jobs', methods=['POST'])
+@_JOB_QUERY_RATE_LIMIT
 def query_jobs():
     """Query jobs for selected resources.
 
@@ -95,6 +115,8 @@ def query_jobs():
     # Validation
     if not resource_ids:
         return jsonify({'error': '請選擇至少一台設備'}), 400
+    if len(resource_ids) > MAX_RESOURCE_IDS:
+        return jsonify({'error': f'設備數量不可超過 {MAX_RESOURCE_IDS} 台'}), 400
     if not start_date or not end_date:
         return jsonify({'error': '請指定日期範圍'}), 400
 
@@ -111,6 +133,7 @@ def query_jobs():
 
 
 @job_query_bp.route('/api/job-query/txn/<job_id>', methods=['GET'])
+@_JOB_QUERY_RATE_LIMIT
 def query_job_txn_history(job_id: str):
     """Query transaction history for a single job.
 
@@ -131,6 +154,7 @@ def query_job_txn_history(job_id: str):
 
 
 @job_query_bp.route('/api/job-query/export', methods=['POST'])
+@_JOB_EXPORT_RATE_LIMIT
 def export_jobs():
     """Export jobs with full transaction history as CSV.
 
@@ -152,6 +176,8 @@ def export_jobs():
     # Validation
     if not resource_ids:
         return jsonify({'error': '請選擇至少一台設備'}), 400
+    if len(resource_ids) > MAX_RESOURCE_IDS:
+        return jsonify({'error': f'設備數量不可超過 {MAX_RESOURCE_IDS} 台'}), 400
     if not start_date or not end_date:
         return jsonify({'error': '請指定日期範圍'}), 400
 
diff --git a/src/mes_dashboard/routes/resource_history_routes.py b/src/mes_dashboard/routes/resource_history_routes.py
index d7659bc..7e01b08 100644
--- a/src/mes_dashboard/routes/resource_history_routes.py
+++ b/src/mes_dashboard/routes/resource_history_routes.py
@@ -4,6 +4,8 @@
 Contains Flask Blueprint for historical equipment performance analysis endpoints.
 """
 
+from datetime import datetime
+
 from flask import Blueprint, jsonify, request, redirect, Response
 
 from mes_dashboard.core.cache import cache_get, cache_set, make_cache_key
@@ -218,6 +220,21 @@ def api_resource_history_export():
             'error': '必須提供 start_date 和 end_date 參數'
         }), 400
 
+    # Validate export date range (max 365 days)
+    try:
+        sd = datetime.strptime(start_date, '%Y-%m-%d')
+        ed = datetime.strptime(end_date, '%Y-%m-%d')
+        if (ed - sd).days > 365:
+            return jsonify({
+                'success': False,
+                'error': 'CSV 匯出範圍不可超過一年 (365 天)'
+            }), 400
+    except ValueError:
+        return jsonify({
+            'success': False,
+            'error': '日期格式錯誤，請使用 YYYY-MM-DD'
+        }), 400
+
     # Generate filename
     filename = f"resource_history_{start_date}_to_{end_date}.csv"
 
diff --git a/src/mes_dashboard/templates/portal.html b/src/mes_dashboard/templates/portal.html
index 24e99ce..983ee96 100644
--- a/src/mes_dashboard/templates/portal.html
+++ b/src/mes_dashboard/templates/portal.html
@@ -423,7 +423,17 @@
 
         function activateTab(targetId, toolSrc) {
             sidebarItems.forEach(item => item.classList.remove('active'));
-            frames.forEach(frame => frame.classList.remove('active'));
+
+            // Unload inactive iframes to free memory and stop their timers
+            frames.forEach(frame => {
+                if (frame.classList.contains('active') && frame.id !== targetId) {
+                    if (frame.src) {
+                        frame.dataset.src = frame.src;
+                    }
+                    frame.removeAttribute('src');
+                }
+                frame.classList.remove('active');
+            });
 
             const activeItems = document.querySelectorAll(`.sidebar-item[data-target="${targetId}"]`);
             activeItems.forEach(item => {