hey, I'm new to vbox and also new to linux and I need some help

I want to use Xfce as my desktop environment but it always automatically starts with GNOME

tutorials say just use the gear button on the user log-in screen but for me there is none

I found a button in the top right which lets me choose between GNOME and Xfce Session but clicking Xfce Session doesn't change anything

https://i.imgur.com/K8zFaTv.png

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I tried uninstalling GNOME via tasksel but it still shows gnome-desktop in the list

https://i.imgur.com/wgdlLSk.png

theres also an "u" next to GNOME and an "i" next to Xfce, does the "u" stand for uninstalled and the "i" for installed?

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maybe this also helps in helping me:

I installed Debian 11 with GNOME -> after that I installed Xfce via tasksel

Now I saw the Gear button in the user log-in screen and I was able to change it to Xfce and everything worked perfectly fine

After that I installed guest additions and after rebooting I always get the User-login screen without the gear button