Enabled Xfwm4 display compositing, both XRender and GL(X), causes the firewall-applet's notification icon appears incorrectly scaled. https://github.com/t-woerner/firewalld/blob/master/src/firewall-applet
Created attachment 6599 firewall-applet's notification icon unscaled - xfwm4 use_compositing true - slowmo
Created attachment 6600 firewall-applet's notification icon scaled - xfwm4 use_compositing false - slowmo
firewall-applet: Use PyQt5 https://github.com/t-woerner/firewalld/commit/fbd7995