I understand that these topics are pretty complex, and really under the hood. If you want to understand them in depth I recommend to read this article:
https://docs.microsoft.com/en-us/dotnet/desktop/wpf/advanced/routed-events-overview?view=netframeworkdesktop-4.8

and this one:

http://www.csharphelper.com/howtos/howto_wpf_tunnel_bubble.html