Dropdown popover offset has a gap if the filtered list falls below a certain point

[chrisolsen]

Replication Steps

1. Small screen resolution (so that dropdown renders above instead of below) (or adjust maxHeight property to be larger)
2. Large list of items
3. Set to filterable
4. Filter to a smaller list (2 items)

More Info

The issue is that the when the popover is first shown it computes the offset based on the max number of items can be shown, but once the list is filtered below that amout the offset is not recomputed, resulting in the white space gap.