Why doesn't button click event “bubble up visual tree” to StackPanel as MSDN article states?

Question

In the MSDN article Understanding Routed Events and Commands In WPF, it states

an event will bubble (propagate) up the visual tree from the source ele

Answer 1

The event bubbles up, until it gets handled...

Since the Button does something with your mouse clicks, it absorbs your mouse event and turns it into a ClickEvent.

If you use the PreviewMouseDown, you see that the StackPanel first receives the event before the button does.. Preview events use the Tunnel down approach..