- 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.cc
GoToOffset(offset);
  return false;
}
void WebContents::FindReply(content::WebContents* web_contents,
                            int request_id,
                            int number_of_matches,
                            const gfx::Rect& selection_rect,
                            int active_match_ordinal,
                            bool final_update) {
  v8::Locker locker(isolate());
  v8::HandleScope handle_scope(isolate());
  mate::Dictionary result = mate::Dictionary::CreateEmpty(isolate());
  if (number_of_matches == -1) {
    result.Set("requestId", request_id);
    result.Set("selectionArea", selection_rect);
    result.Set("finalUpdate", final_update);
    result.Set("activeMatchOrdinal", active_match_ordinal);
    Emit("found-in-page", result);
  } else if (final_update) {
    result.Set("requestId", request_id);
    result.Set("matches", number_of_matches);
    result.Set("finalUpdate", final_update);
    Emit("found-in-page", result);
  }
}
bool WebContents::CheckMediaAccessPermission(