Copy and paste a relative url is turning absolute.

This happens only in WebBrowser control.

STR:
1) Let's have a relative path eg: <a href="\demo">Testing</a> paste this in SOURCE mode into the ckeditor.
2) Switch back to WYSIWYG mode. Select the link -> copy & paste the link to another place of the webpage.

Now, there are two links. Verify the second link. eg. turn into SOURCE mode. You can notice that the relative path turned into absolute: <a href="file:///D:/demo">Testing</a></p>
This happens if the ckeditor served via ISS too. The reslut fullpath will be: <a href="http://localhost/demo">Testing</a></p>
It happens in absolute default environment: Take a windows form and embed a WebBrowser control. I just call the Navigate() method to the _samples\fullpage.html. I tried the with ver. 3.3.1 and ver. 4.2.2. Works the same way. CKEditor loaded into internet browsers does not cause this.
How can I avoid this problem???