Fixing Print Screen in Linux Mint XFCE

To enable Print Screen key functionality in Linux Mint XFCE:

Ensure xfce4-screenshooter is installed:

 sudo apt-get install xfce4-screenshooter  

Then, in the Menu, go to Settings -> Keyboard then Application Shortcuts -> Add. In the Command field, enter xfce4-screenshooter and then click OK, before pressing the Print Screen key on the keyboard, to set that shortcut.