I do use view modes. However, every so often, when I change something else, one or more of my view modes gets reset back to TB's default column setup. It happened to me again a couple of days ago. I recall adding and removing a common folder, plus changing a few filter settings. When I went back to the new common folder I had created, I noticed that it was showing TB's default columns, so I checked the folder's properties and one of my views was ticked. I went to manage views/my view name/edit and sure enough the column settings had been reset. One of the other views had also changed to TB's default.
This is very frustrating when it happens because I have to go through the fiddly procedure of setting things up again.
Actually, while going through this procedure, I have noticed something odd. If I turn message threading off and on, the first column changes width in the message index pane, even though the properties dialogue reports it as being the same width.