Not an answer to the actual question but until it is a feature of xfce4-screenshooter per Artem S. Tashkinov's comment install the Lubuntu app:

sudo apt install screengrab

This answer to "How do I change my keyboard shortcuts in xubuntu?" tells how to change the app invoked by prtscr key from xfce4-screenshooter to screengrab.

Not an answer to the actual question but until it is a feature of xfce4-screenshooter per Artem S. Tashkinov's comment install the Lubuntu app:

sudo apt install screengrab

This answer to "How do I change my keyboard shortcuts in xubuntu?" tells how to change the app invoked by PrtScr key from xfce4-screenshooter to screengrab.

Not an answer to the actual question but until it is a feature of xfce4-screenshooter per https://unix.stackexchange.com/users/260833/artem-s-tashkinov 's comment install the Lubuntu app:

sudo apt install screengrab

How do I change my keyboard shortcuts in xubuntu? answer tells how to change the app invoked by prtscr key from xfce4-screenshooter to screengrab.

Not an answer to the actual question but until it is a feature of xfce4-screenshooter per Artem S. Tashkinov's comment install the Lubuntu app:

sudo apt install screengrab

This answer to "How do I change my keyboard shortcuts in xubuntu?" tells how to change the app invoked by prtscr key from xfce4-screenshooter to screengrab.