diff --git a/js/ui/drop_down_button.js b/js/ui/drop_down_button.js
index 4dd86d35689f..bb5350b3f722 100644
--- a/js/ui/drop_down_button.js
+++ b/js/ui/drop_down_button.js
@@ -13,7 +13,7 @@ import { DataSource } from '../data/data_source/data_source';
 import ArrayStore from '../data/array_store';
 import { Deferred } from '../core/utils/deferred';
 import { extend } from '../core/utils/extend';
-import { isPlainObject, isDefined } from '../core/utils/type';
+import { isObject, isPlainObject, isDefined } from '../core/utils/type';
 import { ensureDefined, noop } from '../core/utils/common';
 import Guid from '../core/guid';
 import { getElementWidth, getSizeValue } from './drop_down_editor/utils';
@@ -545,9 +545,9 @@ const DropDownButton = Widget.inherit({
     },
 
     _getDisplayValue(item) {
-        const isPrimitiveItem = !isPlainObject(item);
+        const isPrimitiveItem = !isObject(item);
         const displayValue = isPrimitiveItem ? item : this._displayGetter(item);
-        return !isPlainObject(displayValue) ? String(ensureDefined(displayValue, '')) : '';
+        return !isObject(displayValue) ? String(ensureDefined(displayValue, '')) : '';
     },
 
     _updateActionButton(selectedItem) {
diff --git a/testing/tests/DevExpress.ui.widgets/dropDownButton.tests.js b/testing/tests/DevExpress.ui.widgets/dropDownButton.tests.js
index bc1b80dc5fb5..17112fe37b01 100644
--- a/testing/tests/DevExpress.ui.widgets/dropDownButton.tests.js
+++ b/testing/tests/DevExpress.ui.widgets/dropDownButton.tests.js
@@ -1912,6 +1912,33 @@ QUnit.module('deferred datasource', {
             assert.strictEqual(this.dropDownButton.option('selectedItem'), null, 'init byKey result is ignored');
         });
     });
+
+    QUnit.test('should display correct text for non-plain objects(T1233565)', function(assert) {
+        class Alignment {
+            constructor(id, name, icon) {
+                this.id = id;
+                this.name = name;
+                this.icon = icon;
+            }
+        }
+        const alignments = [
+            new Alignment(1, 'Left', 'alignleft'),
+            new Alignment(4, 'Right', 'alignright'),
+            new Alignment(2, 'Center', 'aligncenter'),
+            new Alignment(3, 'Justify', 'alignjustify'),
+        ];
+        const instance = new DropDownButton($('#dropDownButton'), {
+            displayExpr: 'name',
+            keyExpr: 'id',
+            selectedItemKey: 1,
+            useSelectMode: true,
+            dataSource: alignments,
+        });
+
+        const textValue = instance.option('text');
+
+        assert.strictEqual(textValue, 'Left', 'the selected item text is properly shown');
+    });
 });
 
 QUnit.module('events', {}, () => {