Context:
When adding a filter to a report that has multiple data sources applied, it is possible to select to which data source that filter should apply.
For filters that display a diagram, switching from one process to another, issues a request to the backend to load the XML of the new diagram.
Doing that currently will just show an empty white space until the new diagram is loaded.

AT:

• Display a loading indicator when switching data sources on the following filters:
  • Filter process instances:
    • Flow Node
    • Flow Node Date : start/end date
  • Filter Flow Nodes:
    • Flow Node selection
    • Duration
    • Flow Node Date: start/end date