Ismael, you Rock!!
Thanks!

Thanks for your though Basilis,

The case from Cesarvega en Ismael is not the same.
There are also other cases but all seem not to apply or the solution is not working in my case.

Thanks all.
What i did was change the background in the Easy slider full width slider with jQuery.

Like this

<script>
jQuery(document).ready(function($) {
	
	  $('#roof_red').click(function() {
	    $('#full_slider_1').css('background-image', 'url(https://www.zonnepanelen-ess.nl/wordpress/wp-content/uploads/2016/04/rode-dakpannen-e1460624616401.png)');
	  });
	  
	  $('#roof_grey').click(function() {
	    $('#full_slider_1').css('background-image', 'url(https://www.zonnepanelen-ess.nl/wordpress/wp-content/uploads/2016/03/dakpan-300x293.jpg)');
	  });
});
</script>

<p align="center"><a href="javascript:void(0);" id="roof_grey">grey</a> | <a href="javascript:void(0);" id="roof_red">red</a></p>

Thanks Elliot for letting me know.

I have found the issue, or better what is causing the problems with the shoppingcart widget.
It is a server setup issue. My server is setup with php fast cgi. This is causing the issue. When i change the server setup using mod php than every thing is working fine.

I still am not sure why this is as it is.
Why is mod php working and php fast cgi not?

It would mean that i should ru n mod php but that is a security risk.

Anny idea about this?!

You have access to the administration part of the site.
So you should be able to see the issue..

Yes, i have:

I removed Enfold theme completely and installed a fresh copy.
AND I removed the child theme and activated the Enfold theme

removed browser cache.
Tried in safari and firefox

So even when i removed the child theme the issue persists in all major browsers.