- 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
Browser::UserTask* out) {
    mate::Dictionary dict;
    if (!ConvertFromV8(isolate, val, &dict))
      return false;
    if (!dict.Get("program", &(out->program)) ||
        !dict.Get("title", &(out->title)))
      return false;
    if (dict.Get("iconPath", &(out->icon_path)) &&
        !dict.Get("iconIndex", &(out->icon_index)))
      return false;
    dict.Get("arguments", &(out->arguments));
    dict.Get("description", &(out->description));
    return true;
  }
};
#endif
}  
namespace atom {
namespace api {
namespace {
int GetPathConstant(const std::string& name) {