* Electron version: 1.6.0, does _not_ repro in 1.4.x
* Operating system: Win32 tested, others possible

It appears that even if you create a window with `focusable: false` and `show: false`, calling `loadURL` on it will cause it to accept window focus and for other windows to lose focus.

### How to reproduce

Open the default Electron app

```js
BW = require('electron').remote.BrowserWindow
let ourWindow = BW.getFocusedWindow()
ourWindow.on('blur', () => console.log("Lost it!"))

hidden = new BW({show: false, width: 500, height: 500, focusable: false})
hidden.loadURL("http://www.yahoo.com")

>>> "Lost it!"
```

This breaks anyone using background windows for computation such as VS Code and Slack (via electron-remote), because whenever a background task kicks off, users can't type anymore
atom/browser/native_window_views.cc
NativeWindow::SetParentWindow(parent);
#if defined(USE_X11)
  XDisplay* xdisplay = gfx::GetXDisplay();
  XSetTransientForHint(
      xdisplay, GetAcceleratedWidget(),
      parent? parent->GetAcceleratedWidget() : DefaultRootWindow(xdisplay));
#elif defined(OS_WIN) && defined(DEBUG)
  
  
  if (parent) {
    ::SetParent(GetAcceleratedWidget(), parent->GetAcceleratedWidget());
    views::Widget::ReparentNativeView(GetNativeWindow(),
                                      parent->GetNativeWindow());
    wm::AddTransientChild(parent->GetNativeWindow(), GetNativeWindow());
  } else {
    if (!GetNativeWindow()->parent())
      return;
    ::SetParent(GetAcceleratedWidget(), NULL);
    views::Widget::ReparentNativeView(GetNativeWindow(), nullptr);
    wm::RemoveTransientChild(GetNativeWindow()->parent(), GetNativeWindow());
  }
#endif
}
gfx::NativeWindow NativeWindowViews::GetNativeWindow() {