* Output of `node_modules/.bin/electron --version`: 2.0.0
* Operating System (Platform and Version): Windows 10

**Expected Behavior**
When I disable a window twice via `setEnabled(false)`, I expect the second disable to have no effect.

**Actual behavior**
The second disable is "queued" up, such that I am forced to enable the window twice to get back to normal.

**To Reproduce**
In the electronquickstart repo, in main.js' `createWindow()`, add these lines:

    mainWindow.setEnabled(false);
    mainWindow.setEnabled(false);
    mainWindow.setEnabled(true);

The window will be disabled when launched. 

You see the same issue if you do it in reverse:

    mainWindow.setEnabled(true);
    mainWindow.setEnabled(false); // this doesn't actually disable it, because the window was enabled from the getgo

If this is expected behavior, can the [docs](https://github.com/electron/electron/blob/master/docs/api/browser-window.md#winsetenabledenable) be updated to explain this behavior.
atom/browser/native_window_views.cc
params.remove_standard_frame = !has_frame();
  if (transparent())
    params.opacity = views::Widget::InitParams::TRANSLUCENT_WINDOW;
  
  
  if (transparent() && !has_frame())
    params.shadow_type = views::Widget::InitParams::SHADOW_TYPE_NONE;
  bool focusable;
  if (options.Get(options::kFocusable, &focusable) && !focusable)
    params.activatable = views::Widget::InitParams::ACTIVATABLE_NO;
#if defined(OS_WIN)
  if (parent)
    params.parent = parent->GetNativeWindow();
  params.native_widget = new AtomDesktopNativeWidgetAura(widget());
  atom_desktop_window_tree_host_win_ = new AtomDesktopWindowTreeHostWin(
      this, widget(),
      static_cast<views::DesktopNativeWidgetAura*>(params.native_widget));
  params.desktop_window_tree_host = atom_desktop_window_tree_host_win_;
#elif defined(USE_X11)
  std::string name = Browser::Get()->GetName();
  
  params.wm_role_name = "browser-window";
  
  params.wm_class_name = base::ToLowerASCII(name);
  params.wm_class_class = name;
#endif
  widget()->Init(params);
  bool fullscreen = false;
  options.Get(options::kFullscreen, &fullscreen);
  std::string window_type;