This problem may occurred due to small height of html and body tag of inner ckeditor iframe.
You can fix it by adding this css code :
Some times your contenteditable="false" may be set to false. So just check it also.
If you are using Firefox there might be some issues. Try to use it in Google chrome.
Hope this will help you. If you still facing the problem let me know.
DNS Gold Member
"Failure is the path of least persistence"