Left menu options inside Appearance> Customize tab not visible after Update

This plugin was doing good but, after updating today it seems some problem. By activating this update I am unable to add new themes and unable to click on Theme Details under Appearance tab. Also the left menu options inside Appearance> Customize tab not visible after update.

Please fix these issue and make this plugin more effective so that we can experience a smooth and faster website.

Regards and wishes-