It would be handy to be able to filter a group's content by owner. Currently its possible to sort on Owner, but there is no filter to just see content shared by one member (searching for member's name doesn't seem to work)
Current problem: Can't change owner for content shared to a group with update capabilities. Unfortunately currently requires me to unshare content from group. Only way for admin to do that is to go to the group with update capabilities and find the content one by one. This is very time consuming, especially when many members have shared content to the group. Also its very difficult to know what group to go to because the items details shows as not shared - even tho the item has actually been shared to a group with update capabilities. note: these issues have been flagged with Esri thru other channels.