Just hit control-O: wherever you are, in some source code directory, the filename column is probably too narrow; so now I have muscle memory that I always have to resize the dialog after opening it. This has been going on for a few months at least. Maybe most people wouldn't notice, because you get GTK dialogs on Gnome and something custom on KDE, but I still use plain X11 so QFileDialog is the widget implementation

It wouldn't surprise me if this bug is in QFileDialog. On the other hand, qtbase/examples/widgets/dialogs/standarddialogs doesn't show this behavior. There, even if I resize the dialog narrower, the column names don't shrink, and they don't stretch either. It's nice to avoid eliding filenames by default, somehow.