ie fadein problem

ie fadein problem

I have a problem with the fadein functionallity in ie.

The problem:
I have a list with categories, when I click one of the categories my list must fadein sorted on that category. In firefox it works like a charm but in ie it fades out but don't fade in. I have checked my page in ie with a debugger. jquery returns me the correct results and loads it in the html but I doesn't fade in on my screen.

Here is my code:
  1. $.post("/ecommerceV2/"+langcode+"/ecommerce/sortPromo",{promotypeid: $(v).val()},function(response){
  2.             $('.assortiment').fadeOut('slow');
  3.             $('.assortiment').load("/ecommerceV2/"+langcode+"/ecommerce .assortiment",{assortiments: response},function(){
  4.       $('.assortiment').fadeIn('slow');
  5. });
  6.  },"json");
Can somebody help me with this?

Greetings