Some Notices

Hello Uranbold,

I can’t reproduce these notices on my installation.

These are just notices that are helpful for developers, they do no harm to the plugin’s/ WordPress function

Would you please deactivate all other plugin except custom sidebar and debug plugin and then check? Please let me know how it goes.

Based from the screenshot I see that you are using the Debug plugin. Would you please try the traditional WordPress debugging? Place the following lines inside the wp-config.php:

define( 'WP_DEBUG', true );
define( 'WP_DEBUG_LOG', true );
define( 'WP_DEBUG_DISPLAY', false );

The notices should be saved to a debug.log log file inside the /wp-content/ directory.

Have an awesome day!

Cheers,
Nastia