Hi Rubie,

There's no built-in dropdowns for column headers, except for the column swap dropdown. If you want your own custom dropdown, then the easier way to handle it would be to use a ContextMenu when the user right-clicks on the header.

If you need more than that, like a button or a dropdown arrow in the header, then you would have to use a CreationFilter to add the button and it would require a lot more code. The dropdown itself could be handled by using PopupControlContainer component which allows you to place any control you want in a dropdown. So you could use a ListView to simulate a dropdown.