- 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
typedef content::NativeWebKeyboardEvent::Modifiers Modifiers;
  int modifiers = event.modifiers;
  modifiers &= ~Modifiers::NumLockOn;
  modifiers &= ~Modifiers::CapsLockOn;
  return (modifiers == Modifiers::AltKey) ||
         (modifiers == (Modifiers::AltKey | Modifiers::IsLeft)) ||
         (modifiers == (Modifiers::AltKey | Modifiers::IsRight));
}
#if defined(USE_X11)
int SendClientEvent(XDisplay* display, ::Window window, const char* msg) {
  XEvent event = {};
  event.xclient.type = ClientMessage;
  event.xclient.send_event = True;
  event.xclient.message_type = XInternAtom(display, msg, False);
  event.xclient.window = window;
  event.xclient.format = 32;
  XSendEvent(display, DefaultRootWindow(display), False,
             SubstructureRedirectMask | SubstructureNotifyMask, &event);
  XFlush(display);
  return True;
}
#endif
class NativeWindowClientView : public views::ClientView {
 public:
  NativeWindowClientView(views::Widget* widget,
                         NativeWindowViews* contents_view)
      : views::ClientView(widget, contents_view) {
  }
  virtual ~NativeWindowClientView() {}
  bool CanClose() override {