As it was stated in Ubuntu MATE 21.10 Release Notes, latest Ubuntu 21.10 has a bug in VTE library which caused GDebi Package Installer breakage when it is launched in GUI way.
We need some time to get this bug fixed in official way.
When GDebi Package Installer is used?
It is used when user downloads some deb-file from trustworthy source (like Skype, Discord, Pandoc and so on) and wants to install it using GUI tool (the gdebi-gtk process) from Caja filemanager. Currently gdebi-gtk is broken.
Temporarily fix for gdebi-gtk is the following - install adapted version of Gdebi from PPA by using the following commands:
sudo add-apt-repository ppa:diddledani/gdebi-fix-1946499
sudo apt-get update
sudo apt-get dist-upgrade
and then use Gdebi Package Installer as it was planned
Note: user can always revert this change by running the following commands - sudo apt-get install ppa-purge && sudo ppa-purge ppa:diddledani/gdebi-fix-1946499 .
