* Electron version: 1.6.5
* Operating system: macOS Sierra

If you have a window with native tab bar to the top and you open a new window, it will open as separate window. But if you are in fullscreen mode, that new window will be attached as tab. Would it make sense to have API to force a window to open into an existing tab group or not? This would make it possible to give the user the choice of wether a window should open as tab or not independent from being in fullscreen mode or not.

Not even sure such API exists on macOS though.

/cc @tonyganch
atom/browser/native_window.h
virtual void Focus(bool focus) = 0;
  virtual bool IsFocused() = 0;
  virtual void Show() = 0;
  virtual void ShowInactive() = 0;
  virtual void Hide() = 0;
  virtual bool IsVisible() = 0;
  virtual bool IsEnabled() = 0;
  virtual void Maximize() = 0;
  virtual void Unmaximize() = 0;
  virtual bool IsMaximized() = 0;
  virtual void Minimize() = 0;
  virtual void Restore() = 0;
  virtual bool IsMinimized() = 0;
  virtual void SetFullScreen(bool fullscreen) = 0;
  virtual bool IsFullscreen() const = 0;
  virtual void SetBounds(const gfx::Rect& bounds, bool animate = false) = 0;
  virtual gfx::Rect GetBounds() = 0;
  virtual void SetSize(const gfx::Size& size, bool animate = false);
  virtual gfx::Size GetSize();
  virtual void SetPosition(const gfx::Point& position, bool animate = false);
  virtual gfx::Point GetPosition();
  virtual void SetContentSize(const gfx::Size& size, bool animate = false);
  virtual gfx::Size GetContentSize();