Why are my windows transparent?

[kingting]

case WM_PAINT:
{

	HDC hdc  = GetDC(hwnd);
	RECT rect;
	GetWindowRect(GetDlgItem(hwnd, ID_SM_SKETCH),&rect); 
	FillRect(hdc, &rect, CreateSolidBrush(GetSysColor(COLOR_3DFACE)));
	ReleaseDC(hwnd,hdc);

	return FALSE;
}
break;