On the profiler tab, the moment I click "Start recording", even before I could move the cursor away from start button, I see there is a continuous stream of change detection cycles. The Source is reported as "Window.addEventListener:message". Please see the screenshot below

1. How can I find what could be causing these events and hence the numerous change detection cycles?
2. As seen in the screenshot there is a method called "changes" listed on the right under the component details. The CasePanelComponent does even have ngOnChanges() method, so what is being referred to here by "changes" method?

Note:
I had raised the same question on StackOverflow but I haven't got any response yet, so raised it here as an issue.