4.2.1: Error in Chrome

I've got "Version 30.0.1599.66" and I haven't encountered any problems (checked 4.2.1 full). Could you describe the situation more precisely? What CKEditor build do you use, on which OS, how do you test? And actually, http://dev.ckeditor.com will be a better place for that.

I see that you're using nested contenteditable elements and that's the problem (I thought that you meant the inline editor). In very short - they are very tricky to be handled by editor, they are behaving differently in every browser and there are a lot of things which can go wrong with them.

That's why, for nearly one year we've been working on the Widget System which is based on noneditable elements and is capable of handling nested editable elements.

Recently, we released CKEditor 4.3 beta which introduces the Widget System. Read more in blog post: http://ckeditor.com/blog/CKEditor-4.3-Beta-Released

There's also a tutorials ready if you'll want to give it a try: http://ckeditor.com/blog/Widget-Tutorials-and-SDK-Published

Note however, that there's a limitation that widget cannot be inserted into another widget's nested editable.