themes - Wordpress customizer extremely slow, cant work in it

I have been adding a couple of settings to my Wordpress admin using this code:

$wp_customize->add_section( 'sectionname' , array(
        'title'      => __'Name',
        'priority'   => 80,
    ) );
$wp_customize->add_setting( 'settingsname' );
$wp_customize->add_control(
    new WP_Customize_Control(
        $wp_customize,
        'settingsname',
        array(
            'label'          => 'Text',
            'section'        => 'sectionname',
            'type'           => 'number',
        )
    )
);

Now the customizer is extremely, after i click a tab in the left handside menu, it freezes and after 30 seconds it loads what was clicked. No errors appears, and everything seems fine, except it is too slow.

I have tried increasing the memory on the server, and it is not that.

The super weird thing is that it is only in Chrome. I have tried this on multiple computers, on chrome it is all the same problem. But when using firefox it works fine.

Any pointers of what it can be would be greatly appreciated! Thanks!