* 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
widget()->CloseNow();
}
void NativeWindowViews::Focus(bool focus) {
  
  if (!IsVisible())
    return;
  if (focus) {
    widget()->Activate();
  } else {
    widget()->Deactivate();
  }
}
bool NativeWindowViews::IsFocused() {
  return widget()->IsActive();
}
void NativeWindowViews::Show() {
  if (is_modal() && NativeWindow::parent() &&
      !widget()->native_widget_private()->IsVisible())
    NativeWindow::parent()->SetEnabled(false);
  widget()->native_widget_private()->ShowWithWindowState(GetRestoredState());
  NotifyWindowShow();
#if defined(USE_X11)
  if (global_menu_bar_)
    global_menu_bar_->OnWindowMapped();
#endif
}
void NativeWindowViews::ShowInactive() {