lightdm-gtk-greeter: disabling "suspend" or other entry

[Andrea Borgia <andrea@borgia.bo.it>]

Hi.

I'm using lightdm-gtk-greeter and I would like to disable some of the 
options, for example "suspend".

I've found a package called lightdm-gtk-greeter-settings but it doesn't 
seem to do what I want: in the "Panel" tab, I can remove the whole 
"power menu" indicator but not drill down and pick a specific sub-option 
to remove.

In a rather old SE thread[1] I saw a suggestion to try polkit so I 
created the PKLA files, rebooted and tried again to select "reboot". I 
am really after disabling "suspend", disabling "reboot" would have been 
just a test and... it didn't work, meaning the system rebooted happily 
also at the second try.

How can I solve this issue?

Thanks,
Andrea.


[1] 
https://askubuntu.com/questions/137336/how-do-i-remove-the-shutdown-button-only-on-the-login-screen