diff --git a/packages/hydrooj/package.json b/packages/hydrooj/package.json
index c5a094e57..40dcd304e 100644
--- a/packages/hydrooj/package.json
+++ b/packages/hydrooj/package.json
@@ -1,6 +1,6 @@
 {
     "name": "hydrooj",
-    "version": "2.23.24",
+    "version": "2.23.25",
     "bin": "bin/hydrooj.js",
     "main": "dist/loader.js",
     "typings": "dist/loader.d.ts",
diff --git a/packages/hydrooj/src/handler/contest.ts b/packages/hydrooj/src/handler/contest.ts
index bdc70fed2..8a0be0c9e 100644
--- a/packages/hydrooj/src/handler/contest.ts
+++ b/packages/hydrooj/src/handler/contest.ts
@@ -218,7 +218,7 @@ class ContestEditHandler extends ContestHandler {
         domainId: string, beginAtDate: string, beginAtTime: string, duration: number,
         title: string, content: string, rule: string, _pids: string, rated = false,
     ) {
-        let pids = _pids.split(',').map((i) => {
+        let pids = _pids.replace(/，/g, ',').split(',').map((i) => {
             if (isSafeInteger(parseInt(i, 10))) return parseInt(i, 10);
             return i;
         });
@@ -422,7 +422,7 @@ class ContestCreateHandler extends ContestHandler {
         domainId: string, beginAtDate: string, beginAtTime: string, duration: number,
         title: string, content: string, rule: string, _pids: string, rated = false,
     ) {
-        let pids = _pids.split(',').map((i) => {
+        let pids = _pids.replace(/，/g, ',').split(',').map((i) => {
             if (isSafeInteger(parseInt(i, 10))) return parseInt(i, 10);
             return i;
         });
diff --git a/packages/hydrooj/src/handler/homework.ts b/packages/hydrooj/src/handler/homework.ts
index 8cd2cc398..9fa314fe0 100644
--- a/packages/hydrooj/src/handler/homework.ts
+++ b/packages/hydrooj/src/handler/homework.ts
@@ -244,7 +244,7 @@ class HomeworkCreateHandler extends HomeworkHandler {
         penaltySinceDate: string, penaltySinceTime: string, extensionDays: number,
         penaltyRules: PenaltyRules, title: string, content: string, _pids: string, rated = false,
     ) {
-        const pids = _pids.split(',').map((i) => {
+        const pids = _pids.replace(/，/g, ',').split(',').map((i) => {
             if (isSafeInteger(parseInt(i, 10))) return parseInt(i, 10);
             return i;
         });
@@ -311,7 +311,7 @@ class HomeworkEditHandler extends HomeworkHandler {
         penaltySinceDate: string, penaltySinceTime: string, extensionDays: number,
         penaltyRules: string, title: string, content: string, _pids: string, rated = false,
     ) {
-        const pids = _pids.split(',').map((i) => {
+        const pids = _pids.replace(/，/g, ',').split(',').map((i) => {
             if (isSafeInteger(parseInt(i, 10))) return parseInt(i, 10);
             return i;
         });
diff --git a/packages/ui-default/components/autocomplete/index.js b/packages/ui-default/components/autocomplete/index.js
index 0fb335cf6..a9695aaf4 100644
--- a/packages/ui-default/components/autocomplete/index.js
+++ b/packages/ui-default/components/autocomplete/index.js
@@ -95,16 +95,21 @@ export default class AutoComplete extends DOMAttachedObject {
 
   onItemClick(ev) {
     const idx = $(ev.currentTarget).attr('data-idx');
-    if (idx === undefined) {
-      return;
-    }
+    if (idx === undefined) return;
     const item = this.currentItems[idx];
     const text = this.options.text(item);
     this._value = item;
     this.$dom.trigger('vjAutoCompleteSelect', item);
     if (text != null) {
       if (!this.options.multi) this.$dom.val(text);
-      else this.$dom.val(`${this.$dom.val() + text}, `);
+      else {
+        const current = this.$dom.val().replace(/，/g, ',');
+        if (current.indexOf(',') !== -1) {
+          const items = current.split(',');
+          items[items.length - 1] = text;
+          this.$dom.val(items.join(', '));
+        } else this.$dom.val(`${text}, `);
+      }
     }
     this.close();
   }
@@ -150,24 +155,23 @@ export default class AutoComplete extends DOMAttachedObject {
   }
 
   close() {
-    if (!this.isOpen) {
-      return;
-    }
+    if (!this.isOpen) return;
     this.dropInstance.close();
     this.isOpen = false;
   }
 
   updateOpenState() {
-    if (this.isFocus && this.$dom.val().length >= this.options.minChar) {
+    let content = this.$dom.val();
+    if (this.options.multi) {
+      content = content.split(',');
+      content = content[content.length - 1].trim();
+    }
+    if (this.isFocus && content >= this.options.minChar) {
       if (!this.isOpen) {
         this.open();
         this.renderList();
       }
-    } else {
-      if (this.isOpen) {
-        this.close();
-      }
-    }
+    } else if (this.isOpen) this.close();
   }
 
   detach() {
diff --git a/packages/ui-default/components/form/form.page.js b/packages/ui-default/components/form/form.page.js
index 6b801d16a..20295b17e 100644
--- a/packages/ui-default/components/form/form.page.js
+++ b/packages/ui-default/components/form/form.page.js
@@ -1,5 +1,5 @@
 import { AutoloadPage } from 'vj/misc/Page';
-import delay from 'vj/utils/delay'
+import delay from 'vj/utils/delay';
 
 const formPage = new AutoloadPage('formPage', () => {
   $(document).on('vjFormDisableUpdate', 'input, select, textarea', (ev) => {
@@ -13,13 +13,14 @@ const formPage = new AutoloadPage('formPage', () => {
   });
 
   const submitting = {};
-
-  $('[type="submit"]').on('click', async (ev) => {
-    if (!submitting[ev.currentTarget]) $(ev.currentTarget).closest('form').submit();
+  $(document).on('click', '[type="submit"]', (ev) => {
+    const $dom = $(ev.currentTarget);
+    if ($dom.attr('name') && $dom.attr('value')) return;
+    ev.preventDefault();
+    if (!submitting[ev.currentTarget]) $dom.closest('form').trigger('submit');
     submitting[ev.currentTarget] = true;
-    await delay(5000);
-    submitting[ev.currentTarget] = false;
-  })
+    delay(5000).then(() => { submitting[ev.currentTarget] = false; });
+  });
 });
 
 export default formPage;
diff --git a/packages/ui-default/package.json b/packages/ui-default/package.json
index a02931f10..9fd3d84ad 100644
--- a/packages/ui-default/package.json
+++ b/packages/ui-default/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@hydrooj/ui-default",
-  "version": "4.6.11",
+  "version": "4.6.12",
   "author": "undefined <i@undefined.moe>",
   "license": "AGPL-3.0",
   "main": "hydro.js",
diff --git a/packages/ui-default/pages/contest_edit.page.js b/packages/ui-default/pages/contest_edit.page.js
index 6aeeb3e67..876a27160 100644
--- a/packages/ui-default/pages/contest_edit.page.js
+++ b/packages/ui-default/pages/contest_edit.page.js
@@ -6,7 +6,7 @@ import i18n from 'vj/utils/i18n';
 import request from 'vj/utils/request';
 
 const page = new NamedPage(['contest_edit', 'contest_create', 'homework_create', 'homework_edit'], (pagename) => {
-  ProblemSelectAutoComplete.getOrConstruct($('[name="pids"]'), { multi: true });
+  ProblemSelectAutoComplete.getOrConstruct($('[name="pids"]'), { multi: true, clearDefaultValue: false });
   if (pagename.endsWith('edit')) {
     let confirmed = false;
     $(document).on('click', '[name="operation"]', (ev) => {