Angular PivotGridFieldChooser - headerFilter
Configures the header filter feature.
A header filter allows a user to filter individual field's values by including or excluding them from the applied filter. Cicking a header filter icon invokes a popup menu displaying all the unique field values.

Assign true to the allowFiltering option to make the icons visible.
allowSearch
Specifies whether searching is enabled in the header filter.
searchTimeout
Specifies a delay in milliseconds between when a user finishes typing in the header filter's search panel, and when the search is executed.