How to provide the quick search functionality for PivotExcelFieldListControl (Customization Form with FieldListStyle="Excel2007")

This example illustrates how to add a search box to the field list control. 
Our PivotExcelFieldListControl uses the TreeViewFieldsPresenter component to show fields in a tree-like view. In this example, we create a TreeViewFieldsPresenter control descendant and implement the filtering functionality at its level.  The default TreeViewFieldsPresenter is replaced with our descendant via styles.