diff --git a/backend/internal/service/websearch_config.go b/backend/internal/service/websearch_config.go
index bb33368d39..d4b0823adc 100644
--- a/backend/internal/service/websearch_config.go
+++ b/backend/internal/service/websearch_config.go
@@ -3,6 +3,7 @@ package service
 import (
 	"context"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"log/slog"
 	"sync/atomic"
@@ -106,6 +107,15 @@ func (s *SettingService) loadWebSearchConfigFromDB() (*WebSearchEmulationConfig,
 
 	raw, err := s.settingRepo.GetValue(dbCtx, SettingKeyWebSearchEmulationConfig)
 	if err != nil {
+		// Missing key is the normal first-boot state: return empty disabled config.
+		if errors.Is(err, ErrSettingNotFound) {
+			cfg := &WebSearchEmulationConfig{}
+			webSearchEmulationCache.Store(&cachedWebSearchEmulationConfig{
+				config:    cfg,
+				expiresAt: time.Now().Add(webSearchEmulationCacheTTL).UnixNano(),
+			})
+			return cfg, nil
+		}
 		webSearchEmulationCache.Store(&cachedWebSearchEmulationConfig{
 			config:    &WebSearchEmulationConfig{},
 			expiresAt: time.Now().Add(webSearchEmulationErrorTTL).UnixNano(),
diff --git a/frontend/src/components/common/BaseDialog.vue b/frontend/src/components/common/BaseDialog.vue
index 2a0f25870b..0a025bfce3 100644
--- a/frontend/src/components/common/BaseDialog.vue
+++ b/frontend/src/components/common/BaseDialog.vue
@@ -28,7 +28,7 @@
           </div>
 
           <!-- Body -->
-          <div class="modal-body">
+          <div ref="modalBodyRef" class="modal-body">
             <slot></slot>
           </div>
 
@@ -52,6 +52,7 @@ const dialogId = `modal-title-${++dialogIdCounter}`
 
 // 焦点管理
 const dialogRef = ref<HTMLElement | null>(null)
+const modalBodyRef = ref<HTMLElement | null>(null)
 let previousActiveElement: HTMLElement | null = null
 
 type DialogWidth = 'narrow' | 'normal' | 'wide' | 'extra-wide' | 'full'
@@ -123,6 +124,9 @@ watch(
 
       // 等待DOM更新后设置焦点到对话框
       await nextTick()
+      if (modalBodyRef.value) {
+        modalBodyRef.value.scrollTop = 0
+      }
       if (dialogRef.value) {
         const firstFocusable = dialogRef.value.querySelector<HTMLElement>(
           'button, [href], input, select, textarea, [tabindex]:not([tabindex="-1"])'
diff --git a/frontend/src/components/common/__tests__/BaseDialog.spec.ts b/frontend/src/components/common/__tests__/BaseDialog.spec.ts
new file mode 100644
index 0000000000..13ada1087e
--- /dev/null
+++ b/frontend/src/components/common/__tests__/BaseDialog.spec.ts
@@ -0,0 +1,37 @@
+import { afterEach, describe, expect, it, vi } from 'vitest'
+import { mount } from '@vue/test-utils'
+import { nextTick } from 'vue'
+import BaseDialog from '../BaseDialog.vue'
+
+vi.mock('vue-i18n', () => ({
+  useI18n: () => ({ t: (key: string) => key })
+}))
+
+describe('BaseDialog', () => {
+  afterEach(() => {
+    document.body.innerHTML = ''
+    document.body.classList.remove('modal-open')
+  })
+
+  it('resets body scroll position when reopened', async () => {
+    const wrapper = mount(BaseDialog, {
+      attachTo: document.body,
+      props: { show: false, title: 'Details' },
+      slots: { default: '<div style="height: 2000px">content</div>' },
+      global: { stubs: { Icon: true } }
+    })
+
+    await wrapper.setProps({ show: true })
+    await nextTick()
+    const body = document.body.querySelector<HTMLElement>('.modal-body')
+    expect(body).not.toBeNull()
+    body!.scrollTop = 480
+
+    await wrapper.setProps({ show: false })
+    await wrapper.setProps({ show: true })
+    await nextTick()
+
+    expect(document.body.querySelector<HTMLElement>('.modal-body')?.scrollTop).toBe(0)
+    wrapper.unmount()
+  })
+})