diff --git a/packages/hydrooj/package.json b/packages/hydrooj/package.json
index ac58466f8..d9ce75298 100644
--- a/packages/hydrooj/package.json
+++ b/packages/hydrooj/package.json
@@ -1,6 +1,6 @@
 {
     "name": "hydrooj",
-    "version": "3.1.0",
+    "version": "3.1.1",
     "bin": "bin/hydrooj.js",
     "main": "src/loader",
     "module": "src/loader",
diff --git a/packages/hydrooj/src/handler/problem.ts b/packages/hydrooj/src/handler/problem.ts
index dbb0b55a5..d9b649947 100644
--- a/packages/hydrooj/src/handler/problem.ts
+++ b/packages/hydrooj/src/handler/problem.ts
@@ -5,9 +5,10 @@ import { lookup } from 'mime-types';
 import { FilterQuery, ObjectID } from 'mongodb';
 import { sortFiles } from '@hydrooj/utils/lib/utils';
 import {
-    BadRequestError, ContestNotAttendedError, ContestNotFoundError, ContestNotLiveError, ForbiddenError, NoProblemError,
-    PermissionError, ProblemNotFoundError, SolutionNotFoundError,
-    ValidationError,
+    BadRequestError, ContestNotAttendedError, ContestNotFoundError,
+    ContestNotLiveError, ForbiddenError, NoProblemError,
+    NotFoundError, PermissionError, ProblemNotFoundError,
+    SolutionNotFoundError, ValidationError,
 } from '../error';
 import {
     ProblemDoc, ProblemStatusDoc, Tdoc, User,
@@ -293,8 +294,10 @@ export class ProblemDetailHandler extends ProblemHandler {
     @param('target', Types.String)
     @param('pid', Types.String, true)
     async postCopy(domainId: string, target: string, pid: string) {
+        const ddoc = await domain.get(target);
+        if (!ddoc) throw new NotFoundError(target);
         const dudoc = await user.getById(target, this.user._id);
-        dudoc.checkPerm(PERM.PERM_CREATE_PROBLEM);
+        if (!dudoc.hasPerm(PERM.PERM_CREATE_PROBLEM)) throw new PermissionError(PERM.PERM_CREATE_PROBLEM);
         const docId = await problem.copy(domainId, this.user.docId, target, pid);
         this.response.redirect = this.url('problem_detail', { domainId: target, pid: docId });
     }
diff --git a/packages/ui-default/package.json b/packages/ui-default/package.json
index 7454b7c4c..b2231e66f 100644
--- a/packages/ui-default/package.json
+++ b/packages/ui-default/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@hydrooj/ui-default",
-  "version": "4.26.1",
+  "version": "4.26.2",
   "author": "undefined <i@undefined.moe>",
   "license": "AGPL-3.0",
   "main": "hydro.js",
diff --git a/packages/ui-default/pages/problem_sidebar.page.ts b/packages/ui-default/pages/problem_sidebar.page.ts
index 9de87123f..e92d54ca7 100644
--- a/packages/ui-default/pages/problem_sidebar.page.ts
+++ b/packages/ui-default/pages/problem_sidebar.page.ts
@@ -1,7 +1,9 @@
 import { NamedPage } from 'vj/misc/Page';
 import tpl from 'vj/utils/tpl';
 import i18n from 'vj/utils/i18n';
-import { ConfirmDialog } from 'vj/components/dialog';
+import request from 'vj/utils/request';
+import { ActionDialog, ConfirmDialog } from 'vj/components/dialog';
+import Notification from 'vj/components/notification';
 
 const page = new NamedPage([
   'problem_create', 'problem_edit', 'problem_solution', 'problem_submit',
@@ -20,6 +22,33 @@ const page = new NamedPage([
       $(ev.currentTarget).closest('form').trigger('submit');
     });
   });
+  $(document).on('click', '[name="problem-sidebar__copy"]', () => {
+    new ActionDialog({
+      $body: tpl`
+        <div class="typo">
+          <label>
+            ${i18n('Target')}
+            <div class="textbox-container">
+              <input name="target" type="text" class="textbox" data-autofocus>
+            </div>
+          </label>
+        </div>
+      `,
+    }).open().then(async (action) => {
+      if (action !== 'ok') return;
+      const target = $('[name="target"]').val();
+      if (!target) return;
+      try {
+        const res = await request.post('', {
+          operation: 'copy',
+          target,
+        });
+        window.location.href = res.url;
+      } catch (error) {
+        Notification.error(error.message);
+      }
+    });
+  });
 });
 
 export default page;
diff --git a/packages/ui-default/static/robots.txt b/packages/ui-default/static/robots.txt
index 731c63e6d..7cf4d17c4 100644
--- a/packages/ui-default/static/robots.txt
+++ b/packages/ui-default/static/robots.txt
@@ -19,5 +19,3 @@ Disallow: /p/*/edit
 Disallow: /d/*/p/*/edit
 Disallow: /p/*/file/
 Disallow: /d/*/p/*/file/
-Disallow: /contest/*/p/*/submit
-Disallow: /d/*/contest/*/p/*/submit
diff --git a/packages/ui-default/templates/partials/problem_sidebar_normal.html b/packages/ui-default/templates/partials/problem_sidebar_normal.html
index cb120de06..7ff933232 100644
--- a/packages/ui-default/templates/partials/problem_sidebar_normal.html
+++ b/packages/ui-default/templates/partials/problem_sidebar_normal.html
@@ -91,7 +91,7 @@
           <span class="icon icon-download"></span> {{ _('Download') }}
         </a></li>
       {% endif %}
-      {% if handler.user.user.hasPriv(PRIV.PRIV_CREATE_DOMAIN) %}
+      {% if handler.user.hasPriv(PRIV.PRIV_CREATE_DOMAIN) %}
         <li class="menu__item nojs--hide"><a class="menu__link" href="javascript:;" name="problem-sidebar__copy">
           <span class="icon icon-copy"></span> {{ _('Copy') }}
         </a></li>