* 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.h
void HandleSizeEvent(WPARAM w_param, LPARAM l_param);
  void SetForwardMouseMessages(bool forward);
  static LRESULT CALLBACK SubclassProc(HWND hwnd,
                                       UINT msg,
                                       WPARAM w_param,
                                       LPARAM l_param,
                                       UINT_PTR subclass_id,
                                       DWORD_PTR ref_data);
  static LRESULT CALLBACK MouseHookProc(int n_code,
                                        WPARAM w_param,
                                        LPARAM l_param);
#endif
  
  void HandleKeyboardEvent(
      content::WebContents*,
      const content::NativeWebKeyboardEvent& event) override;
  
  ui::WindowShowState GetRestoredState();
  std::unique_ptr<RootView> root_view_;
  
  views::View* focused_view_ = nullptr;
  
  
  
  
  extensions::SizeConstraints old_size_constraints_;
#if defined(USE_X11)
  std::unique_ptr<GlobalMenuBarX11> global_menu_bar_;
  
  std::unique_ptr<WindowStateWatcher> window_state_watcher_;