Thanks 
Ashley for these first versions, and also for taking into account the problem with Ajax. It is finally possible, for example, to change the images and other files on runtime (TMX, data etc...) via NW.js, and this is for me something essential because an immense time saving for less repetitive manipulations with each sources modification and other tests.
For now, even if I keep an eye on my C3 licence, I'm forced to continue working with C2, the GUI is there, although aging and sometimes lame, more stable, faster and oriented desktop application than C3. The workspace is much larger (font size and other scaled items), windows and other interactions are stronger, less web-oriented, and there are far fewer bugs, amongst others, when using keyboard shortcuts than I use excessively in C2 (copy / paste / tab next or previous and so on, in forms and image editor included...).
In addition, previews are local and open in their own really separate and persistant window, which avoids having to click often in the taskbar to focus or resize it again and again (just another example according to the context). I hope you understand these thoughts really present in use and in practice when developing. And I hope this native version of C3 will adapt in future to a much more "software" format like C2 is.