External GUI. Windows Forms?

Hi. I’m trying with little success to build an external GUI for a Unity3D game.
The GUI would be a “live” external editor and preferences panel (with lots of IO from/to the user). (100% outside of the game, on top of a c# library on top of Unity3d)

I’m trying to use windows forms, and while I can successfully start a Form, when I try to communicate between threads It just does not work.

So I was wondering that maybe Windows Forms cannot be ran on top of Unity3D or maybe there are better ways of doing this.

Should I use other graphics libraries or other approaches?
Is this even possible?

Thanks to everybody who will help!
Luca

Woah, this is a 2013 question. In case you haven’t figured it out after all these years… Here is my explanation. For me, any commands I execute through Windows Forms to Unity don’t actually execute in Unity until the form is closed. Even if I focus back on Unity, the Unity Window is frozen and nothing happens… I still have no idea how to make the game still run while being on a form. (Yes I tried RunInBackground and nothing)