[fixed] Crash changing Area Light Diffuse Alpha

[micheus]

Dan, as I told I could confirm the error in the install version, but not in my dev one. I checked the current master I have and it already has the problem fixed (I create a installer to test)

I fetched your master branch two days ago. The last commit shows:
Date: Tue Sep 1 20:42:57 2015 +0200

So, it should be something done between the 2.0.1 has been released and that master.