diff --git a/components/Activity/ActivityEditor.tsx b/components/Activity/ActivityEditor.tsx
index 3452ef45..397c462f 100644
--- a/components/Activity/ActivityEditor.tsx
+++ b/components/Activity/ActivityEditor.tsx
@@ -45,6 +45,10 @@ export class ActivityEditor extends PureComponent<ActivityEditorProps> {
     this.detailHTML = detail || '';
   }
 
+  componentWillUnmount() {
+    activityStore.clearCurrent();
+  }
+
   submitHandler = async (event: FormEvent<HTMLFormElement>) => {
     event.preventDefault();
     event.stopPropagation();
@@ -56,7 +60,7 @@ export class ActivityEditor extends PureComponent<ActivityEditorProps> {
     const { name } = this.props,
       data = formToJSON<ActivityFormData>(form);
 
-    data.detail = data.detail + '';
+    data.detail = (data.detail || '') + '';
 
     data.banners = [data.bannerUrls ?? []].flat().map(bannerUrl => {
       const name = bannerUrl.split('/').slice(-1)[0];
@@ -271,13 +275,11 @@ export class ActivityEditor extends PureComponent<ActivityEditorProps> {
             <span className="text-danger"> *</span>
           </Form.Label>
           <Col sm={10}>
-            {detail && (
-              <HTMLEditor
-                name="detail"
-                defaultValue={detail}
-                onChange={code => (this.detailHTML = code)}
-              />
-            )}
+            <HTMLEditor
+              name="detail"
+              defaultValue={detail}
+              onChange={code => (this.detailHTML = code)}
+            />
             <Form.Control
               className="d-none"
               isInvalid={!this.detailHTML.trim() && this.validated}
diff --git a/components/User/UserBar.tsx b/components/User/UserBar.tsx
index b6be9eb3..8ca88dbc 100644
--- a/components/User/UserBar.tsx
+++ b/components/User/UserBar.tsx
@@ -1,5 +1,4 @@
 import { observer } from 'mobx-react';
-import Link from 'next/link';
 import { Button, Dropdown } from 'react-bootstrap';
 
 import sessionStore from '../../models/Session';
@@ -21,9 +20,10 @@ const UserBar = observer(() => {
         </SessionBox>
       ) : (
         <>
-          <Link href="/activity/create" passHref>
-            <Button variant="success">{t('create_hackathons')}</Button>
-          </Link>
+          <Button variant="success" href="/activity/create">
+            {t('create_hackathons')}
+          </Button>
+
           <Dropdown>
             <Dropdown.Toggle>{showName}</Dropdown.Toggle>
             <Dropdown.Menu>
diff --git a/pages/activity/[name]/manage/administrator.tsx b/pages/activity/[name]/manage/administrator.tsx
index c86bd387..5d78d84b 100644
--- a/pages/activity/[name]/manage/administrator.tsx
+++ b/pages/activity/[name]/manage/administrator.tsx
@@ -24,6 +24,7 @@ export default class AdministratorPage extends PureComponent<
 > {
   store = activityStore.staffOf(this.props.route.params!.name + '');
 
+  @observable
   selectedIds: string[] = [];
 
   @observable
diff --git a/pages/activity/[name]/manage/award.tsx b/pages/activity/[name]/manage/award.tsx
index 14a03f2f..3a8c48c5 100644
--- a/pages/activity/[name]/manage/award.tsx
+++ b/pages/activity/[name]/manage/award.tsx
@@ -20,7 +20,7 @@ export const getServerSideProps = withRoute<{ name: string }>();
 const { t } = i18n;
 
 @observer
-class AwardPage extends PureComponent<
+export default class AwardPage extends PureComponent<
   InferGetServerSidePropsType<typeof getServerSideProps>
 > {
   store = activityStore.awardOf(this.props.route.params!.name);
@@ -106,7 +106,7 @@ class AwardPage extends PureComponent<
           </Form.Label>
           <Col sm="9">
             <Form.Select name="target">
-              {Object.entries(AwardTargetName).map(([value, name]) => (
+              {Object.entries(AwardTargetName()).map(([value, name]) => (
                 <option
                   key={name}
                   value={value}
@@ -161,5 +161,3 @@ class AwardPage extends PureComponent<
     );
   }
 }
-
-export default AwardPage;
diff --git a/pages/activity/[name]/manage/git.tsx b/pages/activity/[name]/manage/git.tsx
index fc467768..b8e65b56 100644
--- a/pages/activity/[name]/manage/git.tsx
+++ b/pages/activity/[name]/manage/git.tsx
@@ -22,13 +22,14 @@ export const getServerSideProps = withRoute<{ name: string }>();
 export default class ActivityManageGitPage extends PureComponent<
   InferGetServerSidePropsType<typeof getServerSideProps>
 > {
-  @observable
-  show = false;
-
   store = activityStore.templateOf(this.props.route.params!.name + '');
 
+  @observable
   selectedIds: string[] = [];
 
+  @observable
+  show = false;
+
   handleSubmit = async (event: FormEvent<HTMLFormElement>) => {
     event.preventDefault();
     event.stopPropagation();
diff --git a/pages/activity/[name]/manage/message.tsx b/pages/activity/[name]/manage/message.tsx
index 68b03d61..939ff98a 100644
--- a/pages/activity/[name]/manage/message.tsx
+++ b/pages/activity/[name]/manage/message.tsx
@@ -26,10 +26,11 @@ export default class MessageListPage extends PureComponent<
   form = createRef<HTMLFormElement>();
 
   @observable
-  show = false;
-
   selectedIds: string[] = [];
 
+  @observable
+  show = false;
+
   handleReset = () => this.form.current?.reset();
 
   handleSubmit = async (event: FormEvent<HTMLFormElement>) => {
diff --git a/pages/activity/[name]/manage/organization.tsx b/pages/activity/[name]/manage/organization.tsx
index f31c7619..b47739dd 100644
--- a/pages/activity/[name]/manage/organization.tsx
+++ b/pages/activity/[name]/manage/organization.tsx
@@ -24,6 +24,7 @@ export default class OrganizationPage extends PureComponent<
 > {
   store = activityStore.organizationOf(this.props.route.params!.name);
 
+  @observable
   selectedIds: string[] = [];
 
   @observable
diff --git a/pages/admin/platform-admin.tsx b/pages/admin/platform-admin.tsx
index acafecad..0c13ec35 100644
--- a/pages/admin/platform-admin.tsx
+++ b/pages/admin/platform-admin.tsx
@@ -26,6 +26,7 @@ export default function PlatformAdminPage() {
 class PlatformAdmin extends PureComponent {
   store = new PlatformAdminModel();
 
+  @observable
   selectedIds: string[] = [];
 
   @observable