If you configured a view to display one or more hierarchies, a plus sign (+) appears to the left of the first column heading in the view. Also, a plus sign (+) appears next to a record if you place your mouse cursor over this column in a particular row (as shown below).
Click this this (+) sign to the left of a record to display the list of hierarchies that you added to this view.
Click the the (+) sign to the left of a hierarchy heading to open the sub-view and display the records related to the top-level record via the selected hierarchy. In the example below, the hierarchy displays the Contact Logs for the specified Persons record.
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