KDE and Plasma Netbook: why is hibernation not working?

Question

linux

Changed desktop environment type in KDE 4.5.1 from plasma-desktop to plasma-netbook (System Settings->Workspace->Workspace Type).
Sleep mode stopped working when I closed the lid while I was on battery (System Settings->Power Management->Edit Profiles->Powersave->Actions->When laptop lid closes->Suspend to RAM),
as well as screen lock (pressing a button with the lock does nothing, the shortcut <Ctrl+Alt+l> too).
If I return plasma-desktop in the settings (no reboots or logouts), everything works fine. As well as, however, if you do sudo pm-suspend.

Answer 1

Thank you all in advance, but unfortunately this is a month old bug ...