- Electron version: v0.36.9
- Operating system: Windows 10/OS X

In #779 a `disposition` was added to the `new-window` event in [webContents](https://github.com/atom/electron/blob/master/docs/api/web-contents.md#event-new-window) but it always seems to be set to `new-window` when clicking on target="_blank" links in our web app wrapper: https://github.com/irccloud/irccloud-desktop/blob/v0.1.3/app/main.js#L109

If I Ctrl (Win) or Cmd (OS X) or middle click on links, I would expect to see a `background-tab` disposition, as in Chrome that will open links in a background tab, while keeping focus on the current tab. I'd like to catch this behaviour to set `activate` to false in `shell.openExternal`.

Is this possible?

atom/browser/api/atom_api_web_contents.h
void InsertCSS(const std::string& css);
  bool SavePage(const base::FilePath& full_file_path,
                const content::SavePageType& save_type,
                const SavePageHandler::SavePageCallback& callback);
  void OpenDevTools(mate::Arguments* args);
  void CloseDevTools();
  bool IsDevToolsOpened();
  bool IsDevToolsFocused();
  void ToggleDevTools();
  void EnableDeviceEmulation(const blink::WebDeviceEmulationParams& params);
  void DisableDeviceEmulation();
  void InspectElement(int x, int y);
  void InspectServiceWorker();
  void HasServiceWorker(const base::Callback<void(bool)>&);
  void UnregisterServiceWorker(const base::Callback<void(bool)>&);
  void SetAudioMuted(bool muted);
  bool IsAudioMuted();
  void Print(mate::Arguments* args);
  
  void PrintToPDF(const base::DictionaryValue& setting,
                  const PrintToPDFCallback& callback);
  
  void AddWorkSpace(mate::Arguments* args, const base::FilePath& path);
  void RemoveWorkSpace(mate::Arguments* args, const base::FilePath& path);
  
  void Undo();
  void Redo();
  void Cut();
  void Copy();
  void Paste();