Xfce lock screen really not blanking screen

[Robert Moskowitz]

On a Lenovo x120e.

It makes the screen blank, but does not turn off the video so there is 
this black light on the screen.  My Gnome system (same model, different 
unit) really turns off the video for blanking the screen.

I should also say that the Xfce system is running F21 final RC1.

So am I missing an Xfce screen option, as I am new to Xfce?  Or is 
something not right either in Lenovo support or in F21?