Brief summary of the bug. What is it ? Where is it ?

After removing tenants from a collection, all the heatmap reports will show an infinite loading indicator.

Steps to reproduce:

• Create new a collection
• Create a new dashboard using the "Process  performance overview" template
• Go to sources section of the collection and edit the source used in the dashboard
• Remove all/any of the tenants selected 
• Go back to the dashboard and open it

Actual result:

All the heatmap reports show an infinite loading indicator on the dashboard

Expected result:

All the heatmap reports load as expected

Hints:

It seems that the "xml" field inside the reports (report.data.configuration.xml) is set to "null" after editing the report tenants from the collection.