Subitems:
- Filtering subitems should only be associated to the group you are filtering within not the entire board
- If you filter it should only be specific to the user accessing the board at that time
- The filter order should be a temporary way to view the subitems for the specific user to see what they are looking for, once they are done it should be like Excel where you can remove/clear the filter and the subitems return back to the original order.
- Moving subitems physically should be the only way to alter the original order of the subitems, not the filtering.