- Electron version: `0.37.4`
- Operating system: Windows

When I maximize my [frameless](https://github.com/electron/electron/blob/master/docs/api/frameless-window.md) electron window a small part of the window in an unmaximized state is visible on a secondary monitor.

**Screenshot**
![electronbug](https://cloud.githubusercontent.com/assets/6634592/14762341/8849c728-09bb-11e6-85d8-de12db3fee2d.PNG)

You can visibly see the "line between the monitors" and you can see some really strange overhanging content that is over that line.

**Steps to reproduce**  
1. Open an electron app
2. Maximize the app on your secondary display
3. Look closely for the overflow onto your primary display

This might take a few times to trigger, it appears to do it about 70% of the time :confused: 

atom/browser/native_window_views.cc
wm::SetShadowType(
      GetNativeWindow(),
      has_shadow ? wm::SHADOW_TYPE_RECTANGULAR : wm::SHADOW_TYPE_NONE);
}
bool NativeWindowViews::HasShadow() {
  return wm::GetShadowType(GetNativeWindow()) != wm::SHADOW_TYPE_NONE;
}
void NativeWindowViews::SetIgnoreMouseEvents(bool ignore) {
#if defined(OS_WIN)
  LONG ex_style = ::GetWindowLong(GetAcceleratedWidget(), GWL_EXSTYLE);
  if (ignore)
    ex_style |= (WS_EX_TRANSPARENT | WS_EX_LAYERED);
  else
    ex_style &= ~(WS_EX_TRANSPARENT | WS_EX_LAYERED);
  ::SetWindowLong(GetAcceleratedWidget(), GWL_EXSTYLE, ex_style);
#elif defined(USE_X11)
  if (ignore) {
    XRectangle r = {0, 0, 1, 1};
    XShapeCombineRectangles(gfx::GetXDisplay(), GetAcceleratedWidget(),
                            ShapeInput, 0, 0, &r, 1, ShapeSet, YXBanded);
  } else {
    XShapeCombineMask(gfx::GetXDisplay(), GetAcceleratedWidget(),
                      ShapeInput, 0, 0, None, ShapeSet);
  }
#endif
}
void NativeWindowViews::SetContentProtection(bool enable) {