ExtJs4 event handling. Components event handling

This is continuation of ExtJs4 event handling series. Today we are going to dug into ExtJs Components event handling.
Ext.Component is a core class of ExtJs that is extended by all built-in widgets (like Panel, Grid, etc). So everything I will talk about today may be applied to every widget that extends Ext.Component.

ExtJs4 event handling. DOM Element event handling

Today I want to start new series on ExtJs4 event handling. The series are going to cover topics that might be interesting for beginners (like basic event handling of DOM Elements and ExtJs Components) as well as more advanced event handling related techniques and tricks (like event delegation and best practices for event handling in ExtJs MVC).
Without further ado let's dive into ExtJs4 DOM Elements event handling.