I'm trying to apply a red color outer border for the funnel filtering icon when filter is applied to indicate the filter is active.
Looking at the documentation, I see 4 Path elements for PART_DropDownButton.
But I only see 2 Path elements under DistinctFilterControlTemplate from GridView xaml (as shown in below code block). 2 of the paths from documentation indicate the outer border and background when filtering is applied.
Please guide me here on how to proceed to apply a red border when filtering is active.