While each document resides in a separate window, you can use Taskbar (tabs) to navigate through open files. The interface gives you the convenience of both multi-window and tabbed interface designs. There is a range of document types that are supported, additional types can be defined. The text editor supports word wrap, bookmarks, unlimited undo/redo levels that make editing quite easy for you. While this is a very good, flexible and rich in features tool, it is meant for developers. You would need some time to get familiar with everything you could do with it too.