This is my long abandoned attempt at writing a Doom editor. When I started working on this there were no good Windows editors available, so once that situation changed I stopped working on this project. This was in 2005.
It was once resurrected later in 2008 when UDMF was implemented in ZDoom so that I could create some actual maps in this format.
Note that this requies wxWidgets 2.6.2, it was never tested with any later version and may not work