- 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/atom_browser_client.cc
#include "atom/browser/atom_browser_client.h"
#if defined(OS_WIN)
#include <shlobj.h>
#endif
#include "atom/browser/atom_access_token_store.h"
#include "atom/browser/atom_browser_context.h"
#include "atom/browser/atom_browser_main_parts.h"
#include "atom/browser/atom_quota_permission_context.h"
#include "atom/browser/atom_resource_dispatcher_host_delegate.h"
#include "atom/browser/atom_speech_recognition_manager_delegate.h"
#include "atom/browser/native_window.h"
#include "atom/browser/web_contents_permission_helper.h"
#include "atom/browser/web_contents_preferences.h"
#include "atom/browser/window_list.h"
#include "atom/common/options_switches.h"
#include "base/command_line.h"
#include "base/files/file_util.h"
#include "base/stl_util.h"
#include "base/strings/string_util.h"
#include "base/strings/string_number_conversions.h"
#include "chrome/browser/printing/printing_message_filter.h"
#include "chrome/browser/renderer_host/pepper/chrome_browser_pepper_host_factory.h"
#include "chrome/browser/renderer_host/pepper/widevine_cdm_message_filter.h"
#include "chrome/browser/speech/tts_message_filter.h"
#include "content/public/browser/browser_ppapi_host.h"
#include "content/public/browser/client_certificate_delegate.h"
#include "content/public/browser/render_process_host.h"
#include "content/public/browser/render_view_host.h"
#include "content/public/browser/resource_dispatcher_host.h"