* 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
content::WebContents*,
    const content::NativeWebKeyboardEvent& event) {
  keyboard_event_handler_->HandleKeyboardEvent(event, GetFocusManager());
  if (!menu_bar_)
    return;
  
  if (menu_bar_visible_ && IsAltKey(event))
    menu_bar_->SetAcceleratorVisibility(
        event.type == blink::WebInputEvent::RawKeyDown);
  
  if (event.type == blink::WebInputEvent::RawKeyDown && !IsAltKey(event) &&
      IsAltModifier(event)) {
    if (!menu_bar_visible_ &&
        (menu_bar_->GetAcceleratorIndex(event.windowsKeyCode) != -1))
      SetMenuBarVisibility(true);