win32gui not transparent a color, just transparent all the wwindow

[DQT]

Hello everyone.
I am trying to make a transparent back ground for a Gamemaker studio window,
I fill the background with color (255,255,128)

This is my code:

# '''
import win32gui
import win32con
import winxpgui
import win32api
import subprocess
import time

time.sleep(1)
hwnd = win32gui.FindWindow(None, 'myGame'); #It is my game's name

win32gui.SetWindowLong (hwnd, win32con.GWL_EXSTYLE, win32gui.GetWindowLong (hwnd, win32con.GWL_EXSTYLE ) | win32con.WS_EX_LAYERED )
win32gui.SetLayeredWindowAttributes(hwnd, win32api.RGB(*(255,0,128)), 10, win32con.LWA_ALPHA)
# '''

It just transparent all the window, not a background;
The Notepad's window too.

Thank you for help me.