- 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 PasteAndMatchStyle();
  void Delete();
  void SelectAll();
  void Unselect();
  void Replace(const base::string16& word);
  void ReplaceMisspelling(const base::string16& word);
  uint32_t FindInPage(mate::Arguments* args);
  void StopFindInPage(content::StopFindAction action);
  
  void Focus();
  void TabTraverse(bool reverse);
  
  bool SendIPCMessage(const base::string16& channel,
                      const base::ListValue& args);
  
  void SendInputEvent(v8::Isolate* isolate, v8::Local<v8::Value> input_event);
  
  void BeginFrameSubscription(
      const FrameSubscriber::FrameCaptureCallback& callback);
  void EndFrameSubscription();
  
  void SetSize(const SetSizeParams& params);
  bool IsGuest() const;
  
  void OnEnterFullscreenModeForTab(content::WebContents* source,
                                   const GURL& origin,
                                   bool allowed);
  
  v8::Local<v8::Value> GetWebPreferences(v8::Isolate* isolate);