Only on Chrome on Mac and Chrome canary on Windows (Chrome > 30).
When there is nothing in CKEditor (newly created with blank data) or all the text is removed from CKeditor, clicking on upper part of editor works but if I click lower part of editor, editor would not get focus - cursor would not appear in editor.(Though you can still type.)
It can be reproduced on demo of CKEditor itself. go to http://ckeditor.com/demo. Empty the editor then click outside the editor, when you try to click inside editor on upper part. It won't get focused.
Posted the ticket in CKEditor forum, too. But need quick answer so posting here.
This problem is because of small height of html and body tag of inner ckeditor iframe.
Red line on your picture is just on it's bottom border, inspect your editor by chrome.
To fix it i added this lines to contents.css
html{
height:100%;
}
body
{
height:100%;
}
Always visible vertical scrollbar is acceptable price for me.