ckeditor: '~' character getting encoded in src attribute

I am using ckeditor, v 3.2.1 with Drupal 6.20 (Yes, I tried upgrading ckeditor to latest, with no success).

If I have an img src set to something like "~/someimage.jpg" the src attribute gets encoded to: %7E/someimage.jpg.

But only in FF, not in Chrome, or Ie.

I can see that it is saving the original src attribute in the "_cke_saved_src" attribute cor开发者_JAVA技巧rectly without the ~ encoded. So I assume it's ckeditor that's doing it. I combed through the source code and cannot find what is encoding these. Can someone tell me where and why this is happening and if there's anything I can do to stop it?