Improve selection widgets in the open from DL
Improve selection widgets with search and completion using this: https://developer.gnome.org/gtk3/stable/GtkComboBox.html#gtk-combo-box-new-with-entry
Improve selection widgets with search and completion using this: https://developer.gnome.org/gtk3/stable/GtkComboBox.html#gtk-combo-box-new-with-entry