* Electron version: 1.4.4
* Operating system: win10

Hi,
Example described [here](https://github.com/electron/electron/blob/master/docs/api/global-shortcut.md) works with v1.4.0 but doesn't seem to work with v1.4.4 or v1.4.5.  Method `globalShortcut.isRegistered ` returns true, but the callback isn't called. 

Thanks!
atom/browser/api/atom_api_system_preferences_win.cc
id = COLOR_GRADIENTINACTIVECAPTION;
  } else if (color == "inactive-caption-text") {
    id = COLOR_INACTIVECAPTIONTEXT;
  } else if (color == "info-background") {
    id = COLOR_INFOBK;
  } else if (color == "info-text") {
    id = COLOR_INFOTEXT;
  } else if (color == "menu") {
    id = COLOR_MENU;
  } else if (color == "menu-highlight") {
    id = COLOR_MENUHILIGHT;
  } else if (color == "menubar") {
    id = COLOR_MENUBAR;
  } else if (color == "menu-text") {
    id = COLOR_MENUTEXT;
  } else if (color == "scrollbar") {
    id = COLOR_SCROLLBAR;
  } else if (color == "window") {
    id = COLOR_WINDOW;
  } else if (color == "window-frame") {
    id = COLOR_WINDOWFRAME;
  } else if (color == "window-text") {
    id = COLOR_WINDOWTEXT;
  } else {
    args->ThrowError("Unknown color: " + color);
    return "";
  }
  return ToRGBHex(color_utils::GetSysSkColor(id));
}
void SystemPreferences::InitializeWindow() {