Existing charts can be added to dashboards using the Add Report function, located in the top-right area of the screen. The same chart can be added to multiple dashboards, meaning if the chart is edited, all dashboards with this chart reflect the change.
Clicking Add Report is not the same as clicking Save As in the chart editor.
Add Report merely adds the chart to the dashboard whereas,
Save As creates a version of an existing chart.
Click Add Report. A list of existing charts display.
Search for or click the name of the chart you want to add.
The chart is added to the dashboard.