Comment 3 for bug 1980342

Linux Mint 20.3 Cinnamon - normal installed without any tweaks

The "old" Button (screenshot right side) maybe comes from the previous flatpak installation of Mixxx 2.3.3

Additional info:
At the very beginning of me with Mixxx i installed about 6 month ago both versions (2.3).
Flatpak and the ppa version. The flatpak comes with the old button, the ppa with the new (left side on the screenshot).

I installed the Mixxx 2.4 so in a terminal:
$ sudo add-apt-repository ppa:mixxx/nightlies
$ sudo apt update
$ sudo apt install mixxx