Running a freshly installed Raspberry Pi OS Desktop on a Raspberry Pi 4, I'm trying to install software using the graphical _Add/Remove Software_ tool. For example, Visual Studio Code. After checking the tick near the _code_ entry, I clicked _OK_. A popup appears that additional confirmations are needed because other software has to be changed:

[![enter image description here][1]][1]

I confirmed with _Weiter_ (which means _continue_) but nothing happens. The list appears again and it seems that nothing is working on installing the software, there is no CPU/Network/IO usage.


[![enter image description here][2]][2]

This doesn't change after waiting for a few minutes. The `code` command is also still not avaliable. 

Using `sudo apt install code` on the commandline works, about a minute later VS Code is avaliable using the `code` binary as well as in the application menu of the pixel desktop:

[![enter image description here][3]][3]

The same happens on other packages like `vim`: The GUI doesn't do anything, installing using the terminal works perfectly. I tried to run the _Add/Remove software_ gui using the `pi-packages` command from the terminal, in hope to get some information, but I only get the following lines immediately after startup (without doing anything in the UI):

    $ pi-packages
    
    (pi-packages:5577): Gtk-CRITICAL **: 16:11:10.005: gtk_widget_get_style_context: assertion 'GTK_IS_WIDGET (widget)' failed
    
    (pi-packages:5577): Gtk-CRITICAL **: 16:11:10.005: gtk_style_context_add_class: assertion 'GTK_IS_STYLE_CONTEXT (context)' failed

Why is the GUI not working? What's the problem?

  [1]: https://i.sstatic.net/HDIlD.png
  [2]: https://i.sstatic.net/moAEW.png
  [3]: https://i.sstatic.net/zbQQ3.png