diff --git a/.env.development b/.env.development
index 74e8b0f..40ab90e 100644
--- a/.env.development
+++ b/.env.development
@@ -37,3 +37,6 @@ VITE_AUTOLOGIN_URL=http://localhost:9100/api/sys/autoLogin
 
 # 联系我们
 VITE_GLOB_CONTACT_URL=http://localhost:3100/contact
+
+# 帮助中心
+VITE_GLOB_HELP_CENTER_URL=#
diff --git a/.env.production b/.env.production
index 2eef38f..c8cdc94 100644
--- a/.env.production
+++ b/.env.production
@@ -38,3 +38,6 @@ VITE_AUTOLOGIN_URL=http://200.100.65.101:9100/api/sys/autoLogin
 
 # 联系我们
 VITE_GLOB_CONTACT_URL=#
+
+# 帮助中心
+VITE_GLOB_HELP_CENTER_URL=#
diff --git a/src/layouts/default/header/components/user-dropdown/index.vue b/src/layouts/default/header/components/user-dropdown/index.vue
index d3304db..49191ea 100644
--- a/src/layouts/default/header/components/user-dropdown/index.vue
+++ b/src/layouts/default/header/components/user-dropdown/index.vue
@@ -13,6 +13,7 @@
         <MenuItem itemKey="depart" :text="t('layout.header.dropdownItemSwitchDepart')" icon="ant-design:cluster-outlined" />
         <MenuItem itemKey="cache" :text="t('layout.header.dropdownItemRefreshCache')" icon="ion:sync-outline" />
         <MenuItem itemKey="contact" text="联系我们" icon="ant-design:phone-outlined" />
+        <MenuItem itemKey="helpCenter" text="帮助中心" icon="ant-design:question-circle-outlined" />
 
         <!-- <MenuItem
             v-if="getUseLockPage"
@@ -34,7 +35,7 @@
 
   import { defineComponent, computed, ref } from 'vue';
 
-  import { SITE_URL, CONTACT_URL } from '/@/settings/siteSetting';
+  import { SITE_URL, CONTACT_URL, HELP_CENTER_URL } from '/@/settings/siteSetting';
 
   import { useUserStore } from '/@/store/modules/user';
   import { useHeaderSetting } from '/@/hooks/setting/useHeaderSetting';
@@ -56,7 +57,7 @@ import deptLogo from '/@/assets/images/department-logo.png';
   // import { getFileAccessHttpUrl } from '/@/utils/common/compUtils';
   import { getRefPromise } from '/@/utils/index';
 
-  type MenuEvent = 'logout' | 'doc' | 'lock' | 'cache' | 'depart' | 'contact';
+  type MenuEvent = 'logout' | 'doc' | 'lock' | 'cache' | 'depart' | 'contact' | 'helpCenter';
   const { createMessage } = useMessage();
   export default defineComponent({
     name: 'UserDropdown',
@@ -122,6 +123,11 @@ import deptLogo from '/@/assets/images/department-logo.png';
         openWindow(CONTACT_URL);
       }
 
+      // open help center
+      function openHelpCenter() {
+        openWindow(HELP_CENTER_URL);
+      }
+
       // 清除缓存
       async function clearCache() {
         const result = await refreshCache();
@@ -169,6 +175,9 @@ import deptLogo from '/@/assets/images/department-logo.png';
           case 'contact':
             openContact();
             break;
+          case 'helpCenter':
+            openHelpCenter();
+            break;
           case 'depart':
             updateCurrentDepart();
             break;
diff --git a/src/settings/siteSetting.ts b/src/settings/siteSetting.ts
index c0458a4..d7e9c78 100644
--- a/src/settings/siteSetting.ts
+++ b/src/settings/siteSetting.ts
@@ -9,3 +9,6 @@ export const SITE_URL = 'http://www.jeecg.com';
 
 // contact us url
 export const CONTACT_URL = import.meta.env.VITE_GLOB_CONTACT_URL || '#';
+
+// help center url
+export const HELP_CENTER_URL = import.meta.env.VITE_GLOB_HELP_CENTER_URL || '#';
diff --git a/src/views/tasklist/components/TaskContent.vue b/src/views/tasklist/components/TaskContent.vue
index 9e3c28c..ca354f5 100644
--- a/src/views/tasklist/components/TaskContent.vue
+++ b/src/views/tasklist/components/TaskContent.vue
@@ -433,7 +433,7 @@
 
                 <div v-show="!group.collapsed">
                   <draggable
-                    :model-value="flattenGroupTasks(group.tasks)"
+                    :list="flatListCache[group.id]"
                     :item-key="(ft: any) => ft.task.id"
                     group="tasks"
                     handle=".drag-handle"
@@ -836,7 +836,7 @@
 </template>
 
 <script lang="ts" setup>
-  import { ref, computed, watch, nextTick } from 'vue';
+  import { ref, shallowRef, computed, watch, nextTick } from 'vue';
   import HelpModal from './HelpModal.vue';
   import dayjs from 'dayjs';
   import Icon from '/@/components/Icon/index';
@@ -954,6 +954,27 @@
 
   const localGroups = ref<TaskGroup[]>([]);
 
+  const flatListCache = shallowRef<Record<string, FlatTaskItem[]>>({});
+
+  function rebuildFlatListCache() {
+    const cache: Record<string, FlatTaskItem[]> = {};
+    for (const g of localGroups.value) {
+      cache[g.id] = flattenGroupTasks(g.tasks);
+    }
+    flatListCache.value = cache;
+  }
+
+  watch(
+    () => localGroups.value,
+    () => rebuildFlatListCache(),
+    { immediate: true, deep: true }
+  );
+
+  watch(
+    () => expandedTaskIds.value.size,
+    () => rebuildFlatListCache()
+  );
+
   function showDragBlockedMessage() {
     import('ant-design-vue').then(({ message }) => {
       message.warning('子事项只能在当前父事项下移动');
@@ -1489,13 +1510,13 @@
     const targetGroupEl = toContainer?.closest('[data-group-id]');
     const targetGroupId = targetGroupEl?.dataset?.groupId || '';
 
-    const targetGroup = computedGroups.value.find((g) => g.id === targetGroupId);
+    const targetGroup = localGroups.value.find((g) => g.id === targetGroupId);
     if (!targetGroup) {
       return;
     }
 
-    const rawFlatList = flattenGroupTasks(targetGroup.tasks);
-    const groupIds = new Set(computedGroups.value.map((g) => g.id));
+    const rawFlatList = flatListCache.value[targetGroupId] || [];
+    const groupIds = new Set(localGroups.value.map((g) => g.id));
 
     const draggedIdx = rawFlatList.findIndex((f) => f.task.id === taskId);
     let flatList: FlatTaskItem[];
@@ -1511,8 +1532,8 @@
     if (draggedIdx !== -1) {
       draggedTask = flatList[newIndex]?.task || null;
     } else {
-      for (const g of computedGroups.value) {
-        const found = flattenGroupTasks(g.tasks).find((f) => f.task.id === taskId);
+      for (const g of localGroups.value) {
+        const found = (flatListCache.value[g.id] || []).find((f) => f.task.id === taskId);
         if (found) {
           draggedTask = found.task;
           break;
@@ -1904,6 +1925,16 @@
     display: flex;
     flex-direction: column;
     overflow: hidden;
+
+    :deep(.ant-spin-nested-loading) {
+      height: 100%;
+    }
+    :deep(.ant-spin-container) {
+      display: flex;
+      flex-direction: column;
+      height: 100%;
+      overflow: hidden;
+    }
   }
 
   .content-header {
diff --git a/src/views/tasklist/components/TaskDetailDrawer.vue b/src/views/tasklist/components/TaskDetailDrawer.vue
index 1556c06..5990a6a 100644
--- a/src/views/tasklist/components/TaskDetailDrawer.vue
+++ b/src/views/tasklist/components/TaskDetailDrawer.vue
@@ -282,12 +282,12 @@
                   </button>
                   <span class="feishu-subtask-name" :class="{ done: child.completed }">{{ child.taskName }}</span>
                   <div v-if="!isFullReadOnly" class="feishu-subtask-actions">
-                    <a-tooltip title="设置日期">
-                      <span class="feishu-subtask-action-btn" @click.stop="openSubTaskDateEditor(child.id)">
-                        <Icon icon="ant-design:calendar-outlined" />
+                    <a-tooltip v-if="child.assigneeName" :title="child.assigneeName" placement="top">
+                      <span class="feishu-subtask-avatar" @click.stop="openSubTaskUserSelect(child)">
+                        <AvatarDisplay :names="child.assigneeName" :size="20" />
                       </span>
                     </a-tooltip>
-                    <a-tooltip title="添加负责人">
+                    <a-tooltip v-else title="添加负责人">
                       <span class="feishu-subtask-action-btn" @click.stop="openSubTaskUserSelect(child)">
                         <Icon icon="ant-design:user-add-outlined" />
                       </span>
@@ -298,26 +298,13 @@
                       </span>
                     </a-tooltip>
                   </div>
-                  <div v-if="child.assigneeName && !isFullReadOnly" class="feishu-subtask-avatar" @click.stop="openSubTaskUserSelect(child)">
-                     <a-tooltip :title="child.assigneeName" placement="top"><AvatarDisplay :names="child.assigneeName" :size="20" /></a-tooltip>
-                   </div>
-                   <div v-else-if="child.assigneeName && isFullReadOnly" class="feishu-subtask-avatar">
+                  <div v-else-if="child.assigneeName && isFullReadOnly" class="feishu-subtask-avatar">
                     <a-tooltip :title="child.assigneeName" placement="top"><AvatarDisplay :names="child.assigneeName" :size="20" /></a-tooltip>
                   </div>
                 </div>
               </template>
             </draggable>
 
-            <div v-if="editingSubTask && editingSubTaskField === 'dateRange'" ref="subTaskDateTriggerRef" class="feishu-subtask-date-panel">
-              <TaskDateRangePicker
-                v-model:visible="subTaskDatePickerVisible"
-                :trigger-ref="subTaskDateTriggerRef"
-                :start-value="editingSubTaskStartValue"
-                :end-value="editingSubTaskEndValue"
-                @change="onSubTaskDateRangeChange"
-              />
-            </div>
-
             <div v-if="showNewSubTaskInput && !isFullReadOnly" class="feishu-subtask-row feishu-subtask-input-row">
               <span class="feishu-subtask-drag-placeholder"></span>
               <span class="feishu-subtask-check feishu-subtask-check-empty"></span>
@@ -379,7 +366,7 @@
   import SzUserSelectBySecLevel from '/@/components/semri/userComponent/SzUserSelectBySecLevel.vue';
   import SzDeptUserModal from '/@/components/semri/deptUserComponent/SzDeptUserModal.vue';
   import TaskAttachmentUpload from './TaskAttachmentUpload.vue';
-  import TaskDateRangePicker from './TaskDateRangePicker.vue';
+
   import draggable from 'vuedraggable';
   import dayjs from 'dayjs';
   import { useUserStore } from '/@/store/modules/user';
@@ -428,13 +415,7 @@
   const showRemarkEditor = ref(false);
   const subtaskExpanded = ref(true);
 
-  const editingSubTask = ref<string | null>(null);
-  const editingSubTaskField = ref<string | null>(null);
-  const editingSubTaskValue = ref<any>(null);
-  const editingSubTaskStartValue = ref<string | null>(null);
-  const editingSubTaskEndValue = ref<string | null>(null);
   const subTaskUserSelectId = ref<string>('');
-  const subTaskDatePickerOpen = ref(false);
   const drawerDatePickerVisible = ref(false);
 
   const drawerDateEditMode = ref<'start' | 'end' | null>(null);
@@ -540,9 +521,6 @@
     showDescEditor.value = false;
     showRemarkEditor.value = false;
     subtaskExpanded.value = true;
-    editingSubTask.value = null;
-    editingSubTaskField.value = null;
-    editingSubTaskValue.value = null;
     drawerDatePickerVisible.value = false;
     startTimeDayjs.value = data?.task?.startTime || null;
     endTimeDayjs.value = data?.task?.endTime || null;
@@ -772,29 +750,6 @@
     subTaskUserSelectId.value = '';
   }
 
-  function openSubTaskDateEditor(childId: string) {
-    editingSubTask.value = childId;
-    editingSubTaskField.value = 'dateRange';
-    const child = allTasks.value.find((t) => t.id === childId);
-    editingSubTaskStartValue.value = child?.startTime ? child.startTime.substring(0, 10) : null;
-    editingSubTaskEndValue.value = child?.endTime ? child.endTime.substring(0, 10) : null;
-    subTaskDatePickerOpen.value = true;
-  }
-
-  function onSubTaskDateRangeChange(value: [string | null, string | null]) {
-    if (editingSubTask.value) {
-      emit('update-sub-task-fields', editingSubTask.value, {
-        startTime: value[0] ? value[0] + ' 00:00:00' : '',
-        endTime: value[1] ? value[1] + ' 00:00:00' : '',
-      });
-      editingSubTask.value = null;
-      editingSubTaskField.value = null;
-      editingSubTaskStartValue.value = null;
-      editingSubTaskEndValue.value = null;
-      subTaskDatePickerOpen.value = false;
-    }
-  }
-
   function onSubTaskDragEnd(evt: any) {
     const { oldIndex, newIndex } = evt;
     if (oldIndex === newIndex) return;
diff --git a/src/views/tasklist/components/TaskFlatView.vue b/src/views/tasklist/components/TaskFlatView.vue
index 4f8ab48..91b8b1c 100644
--- a/src/views/tasklist/components/TaskFlatView.vue
+++ b/src/views/tasklist/components/TaskFlatView.vue
@@ -708,6 +708,16 @@
     display: flex;
     flex-direction: column;
     overflow: hidden;
+
+    :deep(.ant-spin-nested-loading) {
+      height: 100%;
+    }
+    :deep(.ant-spin-container) {
+      display: flex;
+      flex-direction: column;
+      height: 100%;
+      overflow: hidden;
+    }
   }
 
   .flat-view-header {
diff --git a/src/views/tasklist/index.vue b/src/views/tasklist/index.vue
index 6625414..bd7fc09 100644
--- a/src/views/tasklist/index.vue
+++ b/src/views/tasklist/index.vue
@@ -844,19 +844,48 @@
     }
   }
 
+  function findTaskInGroups(taskId: string): { group: TaskGroup; task: TaskItem } | null {
+    for (const g of taskListGroups.value) {
+      for (const l of g.taskLists) {
+        for (const tg of l.groups) {
+          const t = tg.tasks.find((t: TaskItem) => t.id === taskId);
+          if (t) return { group: tg, task: t };
+        }
+      }
+    }
+    return null;
+  }
+
   async function onToggleTask(taskId: string) {
+    // 乐观更新：立刻切换 UI
+    if (isFlatView.value) {
+      const idx = flatTasks.value.findIndex((t) => t.id === taskId);
+      if (idx >= 0) {
+        flatTasks.value[idx] = { ...flatTasks.value[idx], completed: !flatTasks.value[idx].completed };
+      }
+    } else {
+      const found = findTaskInGroups(taskId);
+      if (found) {
+        found.task.completed = !found.task.completed;
+      }
+    }
+
     try {
       await toggleTaskStatus({ id: taskId });
+    } catch (e) {
+      console.error('[TaskList] 切换任务状态失败', e);
+      // 回滚
       if (isFlatView.value) {
         const idx = flatTasks.value.findIndex((t) => t.id === taskId);
         if (idx >= 0) {
           flatTasks.value[idx] = { ...flatTasks.value[idx], completed: !flatTasks.value[idx].completed };
         }
-      } else if (currentListId.value) {
-        await loadTasks(currentListId.value);
+      } else {
+        const found = findTaskInGroups(taskId);
+        if (found) {
+          found.task.completed = !found.task.completed;
+        }
       }
-    } catch (e) {
-      console.error('[TaskList] 切换任务状态失败', e);
     }
   }
 
@@ -1057,16 +1086,41 @@
   }
 
   async function onToggleSubTask(taskId: string) {
+    // 乐观更新：立刻切换子任务完成状态
+    if (isFlatView.value) {
+      const idx = flatTasks.value.findIndex((t) => t.id === taskId);
+      if (idx >= 0) {
+        flatTasks.value[idx] = { ...flatTasks.value[idx], completed: !flatTasks.value[idx].completed };
+      }
+    } else {
+      const found = findTaskInGroups(taskId);
+      if (found) {
+        found.task.completed = !found.task.completed;
+      }
+    }
+    refreshDrawer();
+
     try {
       await toggleTaskStatus({ id: taskId });
-      if (isFlatView.value) {
-        await refreshFlatViewTasks();
-      } else if (currentListId.value) {
-        await loadTasks(currentListId.value);
-        refreshDrawer();
-      }
+      refreshDrawer();
     } catch (e) {
       console.error('[TaskList] 切换子任务状态失败', e);
+      // 回滚
+      if (isFlatView.value) {
+        const idx = flatTasks.value.findIndex((t) => t.id === taskId);
+        if (idx >= 0) {
+          flatTasks.value[idx] = { ...flatTasks.value[idx], completed: !flatTasks.value[idx].completed };
+        }
+      } else {
+        const found = findTaskInGroups(taskId);
+        if (found) {
+          found.task.completed = !found.task.completed;
+        }
+      }
+      refreshDrawer();
+      if (currentListId.value) {
+        await loadTasks(currentListId.value);
+      }
     }
   }