Solved : CKEditor 4 AJAX - loading into textarea problems

I have problems with the CKEditor 4 and hope that someone can help me.

I have a textarea (#target) -> an by clicking on different links i´m loading different html code in it with ajax. All is working fine, so i´wanted to change the textarea to ckeditor.

window.onload = function() {
        CKEDITOR.replace('target');
    };

no problem here either.

But when i wanted to change the conted by clicking on "textarea changing links" the ckeditor doesn´t display it. I can see in DOM that the none displayed textarea is still changing its content.

Google tells me previous solutions like :

for ( var target in CKEDITOR.instances ){
           CKEDITOR.instances.target.updateElement();
}

But this didn´t work for me too. It only updates the hidden #target not (the other way) the content in the editor.

How to update the content with ajax?

Has anybody an idea?

Marcel