EditorX(tention) is an framework for building custom windows in the Unity editor. It uses a different design paradigm than vanilla Unity editor scripting. I will touch on it's core concepts briefly in this summary and then expand upon the ideas in depth in this wiki. EditorX replaces Unity's immediate mode EditorUI with an element tree based design like HTML/javascript DOM. Window elements are persistent objects that communicate with the application via attached event listeners (callbacks). Editor Windows are loaded from simple markup, similar to HTML page design. EditorX allows for simple and powerful styling of the elements in the window.
EditorX is extensible and easily supports custom element types and properties. Once your custom element is defined, it is almost no effort to integrate it with the EditorX system. It comes with a lot of features that normalize the Unity Editor scripting interface and bridge the gaps when scripting in Unity Editor windows.
EditorX will allow you to make custom editor windows quickly and easily for any type of editor extension you want to create.
Check out the wiki!

Kameron Brooks
Software Developer - Programmer