- 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_app.cc
content::WebContents* web_contents,
    net::SSLCertRequestInfo* cert_request_info,
    scoped_ptr<content::ClientCertificateDelegate> delegate) {
  std::shared_ptr<content::ClientCertificateDelegate>
      shared_delegate(delegate.release());
  bool prevent_default =
      Emit("select-client-certificate",
           WebContents::CreateFrom(isolate(), web_contents),
           cert_request_info->host_and_port.ToString(),
           cert_request_info->client_certs,
           base::Bind(&OnClientCertificateSelected,
                      isolate(),
                      shared_delegate));
  
  if (!prevent_default)
    shared_delegate->ContinueWithCertificate(
        cert_request_info->client_certs[0].get());
}
void App::OnGpuProcessCrashed(base::TerminationStatus exit_code) {