Set CREATE_NO_WINDOW in tor_spawn_background
The CREATE_NO_WINDOW flag prevents the creation of a console window popup on Windows. We need it for pluggable transport executables under the 3.x browser bundle—otherwise you get blank console windows when you start it up with transports enabled.
In a function called tor_spawn_background it makes sense that console windows shouldn't be popping up. In addition to pluggable transports, I think the function is used for tor-fw-helper.
There may be other ways to solve the problem of console windows, but I haven't been able to think of them.