DimScreen: DimScreen turns ReactOS totally to black

R51583. vBOX.
Dim the whole screen.
http://www.donationcoder.com/Software/Skrommel/DimScreen/DimScreenScreenP.gif

Features:

• Change the brightness by selecting a `% in the tray menu.
• Or use the hotkeys Ctrl++ and Ctrl+-.
• Change hotkeys using Settings in the tray menu.
• Doesn't work properly with video windows.

Could be used for nighttime map reading if your laptop is missing dimming controls.

1)Download from: http://www.donationcoder.com/Software/Skrommel/DimScreen/DimScreen.exe
Source code at: http://www.donationcoder.com/Software/Skrommel/DimScreen/DimScreen.ahk

2)Run it.

3)ReactOS will turn totally to black.

The only line in DebugLog is:
WARNING: NtUserSetLayeredWindowAttributes at subsystems/win32/win32k/ntuser/ntstubs.c:1242 is UNIMPLEMENTED!

(Maybe a Layered window with different transparency degrees?)