ASM Community

hi, i'm filling my window like the following code snippet shows:

invoke CreateSolidBrush,00FFFFFFh
mov wc.hbrBackground,  eax

the window should be white now, right? ok, i'm using backbuffering in that program. every time i update the screen i fill my backbuffer with black, paint the new things on it and copy the backbuffer to my main window's dc with BitBlt. to fill the backbuffer with black i use FillRect. everything works fine. but i've chosen the rectangle so that there should be a white border around the window. do you know what i mean? the rectangle is 5 pixel on every side smaller than the whole window. but the border only appears on the bottom and on the right of the window. above and left, there is a border too, but filled with different colors of pixels. i asked a friend to check the program and above and left there was a black instead of a white border, but why? can you help? snippet of rectangle filling:

mov screenrect.left,5
	mov screenrect.top,5
	mov eax,Wwd
	sub eax,5
	mov screenrect.right,eax
	mov eax,Wht
	sub eax,5
	mov screenrect.bottom,eax
	invoke CreateSolidBrush,00000000h
	mov blackbrush,eax
invoke FillRect, backbuffer, ADDR screenrect, blackbrush