Note: All of the following settings can be configured by Salesforce admins on this page.
Groove for Gmail allows users to log emails and calendar events and "search and select" the related records. By default (meaning, if the field is left blank), Groove searched in these objects for the search query the user entered: Leads, Contacts, Accounts, Opportunities and Cases.
This option allows you to customize in which standard or custom Salesforce objects Groove should search for the search query.
Note 1: Groove will disregard all Salesforce objects that don't have an activity history.
Note 2: If you use this field, the default objects won't be included in search results. So you have to add them explicitly if you still want your users to see search results from Leads, Contacts, Accounts, Opportunities and Cases.