Some time ago we migrated a site collection from 2010 to 2013. Inside this site collection a library contains DocumentSets. We now have this interesting behaviour that sorting in list views does not work properly anymore.
When I sort all DocSets by an arbitrary field (Title, Name, Creation Date, ...) all DocSets which were created on the old 2010 plattform are first sorted correctly and are then followed by all "new" DocSets which have been created after the migration on the new 2013 SharePoint.
When digging deep into the differences between those two kinds of DocSets the only visible difference is that the SortType has changed. All 2010-DocSets were created with
SortType=Folder while all 2013-DocSets were created with
SortType=File. (I guess that this might be due to the change that from 2013 on DocSets can contains sub-folders...)
Unfortunately, this SortTyp is a read-only property, which can only be set on creation of a new ListItem and cannot be changed afterwards (even not when using reflection-magic).
Creating new list view also did not solve the issue.
Does anyone have an idea to fix this sorting issue in list views?