ckeditor removing empty span automatically

You'll find two valid answers in this question: CKEditor strips <i> Tag

One says it's not possible to keep them if you want to see them in the editor and second says that you can prevent them from deleting, but you'll hide them.

I came across this thread with the same problem and thought I'd post my solution. I didn't want CKEditor to remove any blank elements. Add the following to the bottom of your config.js file:

    $.each(CKEDITOR.dtd.$removeEmpty, function (i, value) {
        CKEDITOR.dtd.$removeEmpty[i] = false;
    });

I am using Django CMS 3, CKEditor 4.3 and I got the same problem using twitter bootstrap glyphicon. Looking at : http://ckeditor.com/forums/Support/Prevent-removal-of-empty-span-tags#forum-topic-top.

To allow empty span tag, I have added at the end of ckeditor/config.js

CKEDITOR.dtd.$removeEmpty.span = 0;