Hi,
I think you are testing on the chrome browser, this due to the browser limitation, so have not a good solution to fix this on chrome for now, we will improve it in the future version.
The forum using the "RichTextEditor" not the CuteEditor, so your CuteEditor does not has this skin. If you want to try the RichTextEditor, you can test on http://phphtmleditor.com/demo/ directly.
Regards,
Ken