Wordpress: Unable to view icons next to “Hide Controls” in admin customize.php

[rk0000]

Hi,
I have installed wordpress 5.3.2 on my localhost and everything was fine for 1 month. Suddenly the Mobile view and Desktop view icons are missing from

http://localhost/WordPress/wp-admin/customize.php

I have disabled all the plugins and deleted unused themes but still no use.
have updated the wordpress to 5.5.1, but the issue remains there.
The other details are:
mysql –version
mysql Ver 15.1 Distrib 10.4.14-MariaDB, for Win64 (AMD64), source revision ddffcad64c9ff3299037eed9df1bc92d51f8d07e
httpd -v
Server version: Apache/2.4.46 (Win64) Apache Lounge VC15 Server built: Aug 4 2020 11:50:23
php -v
PHP 7.4.9 (cli) (built: Aug 4 2020 11:52:41) ( ZTS Visual C++ 2017 x64 ) Copyright (c) The PHP Group Zend Engine v3.4.0, Copyright (c) Zend Technologies