Check why beginInsertRows()/endInsertRows() is not working in TopLevelItemModel
The TopLevelItemModel is listening for addition of new items to a library. When this happens, it currently uses beginResetModel() and endResetModel() to let attached viewed know about the change. This however is not very quick, as it leads to complete redraws or re-filtering/sorting in proxy models. There was a try to use beginInsertRows()/endInsertRows() instead, which would be much quicker, but these did not seem to show any effect. This should be reviewed to get a better performance.