I have a simple NSOutlineView which works nice so far. The only thing I did not get to work is when I issue a reloadData(). Where I have an expanded item and the reason for the reload was that one child was added then the new child does not appear. The parent is refreshed as I see that the number of children (which I output too) is updated. The new child however does not appear.
I circumvented this behavior by collapsing the parent when adding or deleting child items. But I wonder if there is any trick to get the children get refreshed as well maintaining the expansion state of a parent as it is.
Could you use reloadItem:reloadChildren: on the NSOutlineView when you want to reload? If you want to refresh everything just reload the root item by passing 'nil' for the first parameter.