I'm running CKeditor 3 and have noticed that when I paste a form field in to source and hit save. If I then reload the page and open up the editor, the form tags have been replaced by a p tag.
How can I fix this without upgrading to ckeditor4?
Its an issue of browser, and not a CKEditor: http://dev.ckeditor.com/ticket/8590 . As a short conclusion, here is the quote:
If browser strips down the nested form then this means that CKEditor receives this reduced code. There is no way CKEditor can get to that code before the browser so it simply does not know about the missing form tag.