Setting imageUrl client-side doesn't work

[JP]

Hello,

I'm adding new values to the comboBox client-side, including an icon. Unfortunately, the image won't work. In fact, all icons of already existing items (which were added server-side) disappear. The imageUrl is correct, I also used the imageUrl of the currently selectected item.

This is my code:

var caption = "Test";
var id = "123";
var img = "inc/img/Ps/Img1.png"

  var items = this.get_comboBox().get_items();
      this.get_comboBox().trackChanges();
      var comboItem = new Telerik.Web.UI.RadComboBoxItem();
      comboItem.set_text(caption);
      comboItem.set_value(id);
      comboItem.set_imageUrl(img);

      items.add(comboItem);
      this.get_comboBox().commitChanges();

Am I missing something?

Edit: If I don't set the ImageUrl to the client-side item, the other icons disappear anyway.

[JP]

Found the problem: I was using a sort function afterwards - thereby the imageUrl got lost.