Nemo Action on Desktop not appearing

Question

I have this .nemo_action file in ~/.local/share/nemo/actions, but it does not have any effect:

[Nemo Action]                                                                                        
Active=true                                                                                             
Exec=/usr/bin/xfce4-display-settings                                                                    
Icon-Name=preferences-desktop-display                                                                
Selection=none                                                                                       
Extensions=any;                                                                                      
Conditions=desktop;                                                                                  
Name=Change Displays                                                                                 
Comment=Rearrange displays

I've also tried varying Extensions to none and varying the path of Exec, but nothing shows up. The reference file says this should work AFAICT, and online guides say that there shouldn't be any need to restart the system, re-initialize Nemo, etc.

So what's wrong?