First trial rendering with beta24 seems the gray bug fixed

That's just what I wanted you (and others) to test. Thanks for the good news. [:)]

But it does not works fine like v4.3

You have to compare with the version 4.3 running under Java Web Start with Java 7/8. You probably use the installer version 4.3 which is bundled with Java 6, not Java 7/8, and Java 6 will continue to come with the installer of version 4.4.

1. Could you please check that the skylight and IBL light works together and gives over brightness at mid day in Arial view?.

I remember that this didn't work correctly, and won't renew the tests now. As you seem to be able to modify the code, feel free to test it on your side.

2. At the exact time 4.04AM gives me a slighter moon light effect. I wish more light with the same sky in the scene can give exact moon light effect.

Sorry, I won't manage the moon, just because the night hour is convenient for the users who want to manage all their lights, without having a default light.

3. In a night scene by increasing the size of bulb(light),why coverage area of light reduces?

I just tested again and didn't really see a difference of light power on a scene that contains just a light.

4. Adding self illumination glow can solve tubular/neon light effect. Is it possible?

I don't see what you mean, searching "glow" in SunFlow source code gives nothing.

5. Could you please check that why temp file in folder(%AppData%\Roaming\eTeks\Sweet Home 3D\work) duplicates the plugins folder content?

It's on purpose. Otherwise, it would be impossible (or much more complicate) to allow the user to import a .sh3f / .sh3t file that overwrites an existing one, without relaunching the program. If you don't want this copy to be made, select the Read only attribute on .sh3f files in %AppData%\Roaming\eTeks\Sweet Home 3D\furniture folder and on .sh3t files %AppData%\Roaming\eTeks\Sweet Home 3D\textures folder.