Item width in QListView

[bepaald]

Hi, I'm trying to implement my own file dialog. Right now it contains a QListView with a QFileSystemModel as its model. It seems to do what I expect it to at this point, but I'm wondering why the items in my listview take up an entire column while those in the standard QFileDialog only take up as much space as the filename. I've attached two screenshots to show what I mean:
50785079

So, how can I get the behaviour as seen in the standard QFileDialog? Also, if anybody could explain why the two dialogs use different sorting rules I'd like to hear it.

Thanks,
bepaald