[RESOLVED] Strange stretching

[AKE]

Strange behaviour of my application.
In windows 7 - all work
In windows xp after stretching main window - application close.
Code of sizing:

	case WM_SIZE:
        SendMessage(hsb, WM_SIZE, 0, 0);
		{RECT WindowRect;
        GetWindowRect(hwnd, &WindowRect);
		int width = WindowRect.right-WindowRect.left;
		SetWindowPos(hProgress, HWND_BOTTOM, 20, 150, width-50, 17, 0); 
		break;}

In what problem?