Well, I installed xfce4, just a few hours working, more than 4 hours.
After that, configured xfce4, I've entered in the desktop environment, everything OK, just a
little issue, Thunar, the file manager is not installed.
Thunar has not a binary package to install from, then it should be compiled from ports.
Let's do that...
A few hours downloading, compiling, making packages, and installing them.
But, thunar depends on a big "monster", "texlive-texmf-20150523_4", this "monster", just 1.8 GB size, has not a binary package too.
After that, more than 4 hours to download the file, and 4 hours more to build/compile, and 50 minutes to install the package.
The story follows, several hours more compiling, etc., and all finished with an unrecoverable error that I can recall now.
Conclusion: xfce4 is not working at all, and Midnight is very useless as desktop environment OS.
I have deleted all the O.S., that's all.
I expect in the future, MidnightBSD has better things to offer.