Fix: Problematic CSS enqueue

This plugin has a problematic css enqueue, that messes up checkboxes in admin, because of the slider.css that is enqueued for the backend switches.
( slider.css applies a position:absolute to any element with the class .checked )

As a quick fix add this to your functions.php:

function remove_datetimepicker_css(){
    if ( !isset($_GET['page']) || $_GET['page'] != 'dtpicker' ) {
        wp_dequeue_style('dtpkr-slider-style');
    }
}
add_action( 'admin_enqueue_scripts', 'remove_datetimepicker_css', 100 );