The lack of a thumbnail is hardly the most glaring flaw in gtkfilechooserwidget.c in Gtk3. Since 2013 (before this it was fine) the file chooser File->Open dial

The lack of a thumbnail is hardly the most glaring flaw in gtkfilechooserwidget.c in Gtk3. Since 2013 (before this it was fine) the file chooser File->Open dialog no longer allows you to type in it or paste file paths into without first hitting a series of hot keys. It will literally throw an error if you paste a file path into the file chooser. This means every application that uses Gtk3 is broken on linux. I've talked to the devs responsible for this over on their GNOME IRC channel and they say everyone should port their applications to Gtk4 and Gtk3 is frozen and will never be fixed. I've attempted to fix it myself in source, compile, and manually swap in the new gtk3 libs but so far I can only get the filename entry text box to appear by default on the first "File->Open" operation but none after the first. It is one of the major reasons I run older versions of software. Newer software is broken unless it is bleeding edge and then nothing actually uses it.