* Electron version:1.4.14
* Operating system: mac v10.12.3

### Expected behavior

setting  BrowserWindow options frame false

browser Top frame zone 

There is an invisible window

<!-- What do you think should happen? -->

i want work css cursor:pointer

my option code

	mainWindow = new BrowserWindow({
            show: false,
            frame: false,// look
            title: "",
            useContentSize: false,
            width: mainWindowWidth,
            minWidth: mainWindowWidth,
            height: mainWindowHeight,
            minHeight: mainWindowHeight,
            maximizable:false,
            fullscreenable:false,
            icon: iconPath
        });


atom/browser/native_window_mac.h
bool HasShadow() override;
  void SetRepresentedFilename(const std::string& filename) override;
  std::string GetRepresentedFilename() override;
  void SetDocumentEdited(bool edited) override;
  bool IsDocumentEdited() override;
  void SetIgnoreMouseEvents(bool ignore) override;
  void SetContentProtection(bool enable) override;
  void SetBrowserView(NativeBrowserView* browser_view) override;
  void SetParentWindow(NativeWindow* parent) override;
  gfx::NativeView GetNativeView() const override;
  gfx::NativeWindow GetNativeWindow() const override;
  gfx::AcceleratedWidget GetAcceleratedWidget() const override;
  void SetProgressBar(double progress, const ProgressState state) override;
  void SetOverlayIcon(const gfx::Image& overlay,
                      const std::string& description) override;
  void SetVisibleOnAllWorkspaces(bool visible) override;
  bool IsVisibleOnAllWorkspaces() override;
  void SetAutoHideCursor(bool auto_hide) override;
  void SetVibrancy(const std::string& type) override;
  void SetTouchBar(
      const std::vector<mate::PersistentDictionary>& items) override;
  void RefreshTouchBarItem(const std::string& item_id) override;
  void SetEscapeTouchBarItem(const mate::PersistentDictionary& item) override;
  
  void OnInputEvent(const blink::WebInputEvent& event) override;
  
  void RenderViewHostChanged(content::RenderViewHost* old_host,
                             content::RenderViewHost* new_host) override;
  
  void UpdateDraggableRegionViews() {