Action bubbling down

In HTML element space, when a child and parent element has separate actions and when the child element is clicked, first the child action is invoked, and then the parent action is invoked.

However when the child is a Ember component, parent action is invoked first and then the child component action is invoked. Why is that difference in behaviour?

codes:

Case “parent and child are HTML elements”

Case “parent is HTML element and child in ember component”