From bcec68f783191fcd14b97450eebb067ed45a1ad4 Mon Sep 17 00:00:00 2001
From: Andrew Telnov <andrew.telnov@gmail.com>
Date: Wed, 19 Jun 2024 10:26:56 +0300
Subject: [PATCH] "None" choice in checkbox question is not deselected on
 clicking on it when it is selected fix #8438

---
 src/question_checkbox.ts          |  2 +-
 tests/question_baseselecttests.ts | 19 +++++++++++++++++++
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/src/question_checkbox.ts b/src/question_checkbox.ts
index 2e5cc33393..4abb7e541c 100644
--- a/src/question_checkbox.ts
+++ b/src/question_checkbox.ts
@@ -167,7 +167,7 @@ export class QuestionCheckboxModel extends QuestionCheckboxBase {
       }
     } else {
       if(this.isNoneItem(item)) {
-        this.renderedValue = [item.value];
+        this.renderedValue = checked ? [item.value] : [];
       } else {
         const newValue: Array<any> = [].concat(this.renderedValue || []);
         const index = newValue.indexOf(item.value);
diff --git a/tests/question_baseselecttests.ts b/tests/question_baseselecttests.ts
index da661d9d57..65a02d0b3f 100644
--- a/tests/question_baseselecttests.ts
+++ b/tests/question_baseselecttests.ts
@@ -2160,3 +2160,22 @@ QUnit.test("valuePropertyName & complete trigger, bug#8434", (assert) => {
   q.renderedValue = ["none"];
   assert.equal(survey.calcIsCompleteButtonVisible(), true, "#4");
 });
+QUnit.test("Unselect none item, bug#8438", (assert) => {
+  const survey = new SurveyModel({
+    "elements": [
+      {
+        "type": "checkbox",
+        "name": "q1",
+        "choices": [1, 2, 3],
+        "showNoneItem": true
+      }
+    ]
+  });
+  const q = <QuestionCheckboxModel>survey.getQuestionByName("q1");
+  q.clickItemHandler(q.noneItem, true);
+  assert.deepEqual(q.value, ["none"], "#1");
+  q.clickItemHandler(q.noneItem, false);
+  assert.equal(q.isEmpty(), true, "#2");
+  q.clickItemHandler(q.noneItem, true);
+  assert.deepEqual(q.value, ["none"], "#3");
+});