As per the Ext documentation:
"While some Ext JS Component classes export selected DOM events (e.g. "click", "mouseover" etc), this is usually only done when extra value can be added. For example the DataView's itemclick event passing the node clicked on. To access DOM events directly from a child element of a Component, we need to specify the element option to identify the Component property to add a DOM listener to."
It's SUPER IMPORTANT to associate data with the store.
If you specify data here it is provided to the tpl, but not properly bound to the store. Unless the store knows about the data itemclick events won't work.