It would be useful to add some features.
1. To display empty folders in the sessions tree. While dragging sessions between folders, folders may disappear if got empty.
So, it become impossible to drop any sessions to such folders.
2. To add the possibility to request before open all sessions in the folder by double click.
Sometimes such double clicks are accidental, and closing many needless sessions is annoying thing.
For now, it's not possible to create empty folder, the database structure does not allow, but this might change eventually. The second point is already added in our internal build. this will be in the next update.