open/save-dialog of some software: files and documents are mixed without separation
Steps to reproduce
open firefox
press ctrl+O
in the column header: press Name
Current behavior
in open/save-dialog: when Name is pressed in the column header:
files and documents are in an alphabetical order, but without separation
Expected outcome
in open/save-dialog: when Name is pressed in the column header:
first come the files, then come the documents (or other way around), each in an alphabetical order (alphabetical order: top-bottom or bottom-top)
Version information
Lubuntu 20.10
Additional information
the problem appears not only in firefox, but also in other software, like geany and audacity
in Lubuntu 20.10, this problem does not occur in LibreOffice, because there LibreOffice does not use GTK but LXQt File Dialog