Colum filter performance

[lostluna1]

Regarding the performance issue of header filtering, if my dataset is at the 10K level, it takes several seconds for the UI to respond after clicking on the filter. Personally, I believe that column header filtering exists because I am too lazy to do pagination

[w-ahmad]

The reason it is slow is because there is ItemsControl hosted in ScrollViewer to show filter items without virtualization. Replacing these controls with a ListView could significantly enhance the performance of the filter flyout.

[w-ahmad]

created bug from this discussion #65