Google Drive documents results used to be shown below Gmail search results. That option was a labs enabled tool where when you searched Gmail you would see matching Google Drive documents below the email results. Is there a way to re-enable that? It appears Google has disabled that function.
This is a "Google Apps for Business" account.
"Apps Search" does not appear under Labs in Settings for any users even though it is enabled in Domain Admin > Apps > Google Apps > Settings for Gmail > Labs
Best Answer
Google is releasing a new "integrated search experience", which allows you to search Gmail, Google Calendar, Google Groups and Google Drive all from the search bar. It's working for me now, and is very similar to the old "Apps Search" lab.
However, it looks like it may only be rolled out to G Suite customers ("G Suite" was formerly known as "Google Apps for Work").
Here is the announcement:
https://gsuiteupdates.googleblog.com/2016/10/integrated-search-now-available-in-gmail-drive-groups-calendar.html