Comment 10 for bug 964433

It turns out that the problem is that:
- in appview.py we call model.set_from_matches()
- this will load a initial batch of rows and the add empty placeholder rows
- because the apptreeview has a _cell_data_func the rows are requesting data
- this causes load_range to be run and that will load the documents that were meant to be empty and loaded on demand

The fix is to disconnect the model first and then after its updated set it again.