We have introduced the shared data source functionality for widgets on the same dashboard.
In particular, it means that when there are multiple widgets on the same dashboard, each widget can reuse the data source of the other widgets. The available data sources from other widgets are grouped in a separate group called Existing data source which appears when you click the 
Add Source option.
To avoid conflicts, the data source labels are now configurable through the edit icon 
and every data source must have a unique label within the dashboard. The fact that the data source is shared is indicated by the link icon 
next to its label.
The shared data sources optimize the process, lead to faster loading times, and reduce the number of requests to the backend when a data source is called.
Find out more in the user guide for the respective widgets, for example the Tree widget.