Apparently, this was fixed in garcon (Xfce's menu library).
Xubuntu 18.04 includes version 0.6.1, and is therefore not affected by this bug anymore.
https://git.xfce.org/xfce/garcon/tree/NEWS
Apparently, this was fixed in garcon (Xfce's menu library).
Xubuntu 18.04 includes version 0.6.1, and is therefore not affected by this bug anymore.
https:/ /git.xfce. org/xfce/ garcon/ tree/NEWS