Hawtio:Runtime: non-functional sorting in Native column of Threads tab

Expected:
There is executed some sorting according to Native column content. The Native column is filled by dots, I would expect that while ascending sorting, the empty cells come first. While descending, I would expect that cells with dots come first. This is just my expectations, I'm not sure how exactly sorting by this column should work.

Actual:
After clicking on Native column, nothing is changed.