SeaMonkey has part(s) Mozilla Composer
Components
SeaMonkey consists of a web browser, which is a descendant of the Netscape family, an e-mail and news client program (SeaMonkey Mail & Newsgroups, which shares code with Mozilla Thunderbird), an HTML editor (SeaMonkey Composer) and an IRC client (ChatZilla). The software suite supports skins. It comes with two skins in the default installation, Modern and Classic.Composer
SeaMonkey Composer is a WYSIWYG HTML editor descended from Mozilla Composer. Its main user interface features four tabs: Normal (WYSIWYG), HTML tags, HTML code, and browser preview. The generated code is HTML 4.01 Transitional.
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