- 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
const std::string& name,
                  const base::FilePath& path) {
  bool succeed = false;
  int key = GetPathConstant(name);
  if (key >= 0)
    succeed = PathService::Override(key, path);
  if (!succeed)
    args->ThrowError("Failed to set path");
}
void App::SetDesktopName(const std::string& desktop_name) {
#if defined(OS_LINUX)
  scoped_ptr<base::Environment> env(base::Environment::Create());
  env->SetVar("CHROME_DESKTOP", desktop_name);
#endif
}
void App::AllowNTLMCredentialsForAllDomains(bool should_allow) {
  auto browser_context = static_cast<AtomBrowserContext*>(
        AtomBrowserMainParts::Get()->browser_context());
  browser_context->AllowNTLMCredentialsForAllDomains(should_allow);
}
std::string App::GetLocale() {
  return l10n_util::GetApplicationLocale("");
}
#if defined(OS_WIN)
bool App::IsAeroGlassEnabled() {
  return ui::win::IsAeroGlassEnabled();
}
#endif
bool App::MakeSingleInstance(