jWysiwyg: Textarea appears below editor

plug-in: JWysiwyg

my settings:
there's an "editor" input format for logged users, while anonymous just use the default input format, "basic". "editor" input format works with WYSIWYG by default (logged users can disable it and switch to "basic"), while "basic" has no wysiwyg (with no other input format available to anonymous users).

the problem:
when accessing node publishing pages as logged users textareas show twice, first as wysiwyg boxes then right below as simple textarea with no editor. (see attached screenshot)

by the way, the text in the wysiwyg textarea is displayed while typed in the simple-text textarea below (but not the other way around).

if I disable wysiwyg editor and enable it again, then just one textarea with editor is displayed, as expected.

[replicated on both Firefox and Safari]