A few small fixes:
1) SetFilter prevents list from being sorted with a FastOLV. Call _BuildInnerList if innerList is not the same list as modelObjects. (First reported by Yoav Glazner)
2) GroupListView's group headers don't get refeshed with an updated title/count sometimes. Added check to GLV's AddObjects (only updates necessary items, as I read somewhere that you hate flicker ;) )
3) The state of the GroupListView's collapsed groups is lost when you repopulate or AddObjects. Added a dict that keeps track of the group header states, made isExpanded a property to retain compatibility and minimize changes to the rest of the code.
4) This is not an issue but I wanted the ability to hide the expansion column with a GLV, so I added the expansionColumnWidth keyword argument.
Apologies for the misdirected email regarding this.