Wikipedia
KompoZer
KompoZer is an open source WYSIWYG HTML editor based on the now-discontinued Nvu editor. KompoZer is maintained as a community-driven fork, and is a project on Sourceforge. However, the project appears to be inactive: the sourceforge page indicates no new files in five years.
The current pre-release is KompoZer 0.8 beta 3, released February 2010, using Gecko 1.8.1. The stable version was 0.7.10, released in August 2007. The only regular developer said in June 2011 that development "is stalled at the moment".
KompoZer's WYSIWYG editing capabilities are one of the main attractions of the software. In addition, KompoZer allows direct code editing as well as a split code-graphic view.