Event Handler stops working on grid view change and column change

Question

The issue that I am having pertains to ExtJS 3.4

I have two issues :

1. If after applying change handlers onto a select dropdown I move the column or change the Grid View (which also can move columns). The 'change' handler breaks. The name of the select drop down remains the same but does not fire the 'change' event.
2. There is an additional drop-down that allows you to change the type of document you are creating. And this essentially changes the name of the element. This makes sense that the handler wont handle the event. However is there a way to listen for element name change and add the previous handler to the new element?

// Current code to add on change handler
Ext.get(Ext.DomQuery.select("select[name='" + item + "']")[0]).on('change', me.handleOnChange);