Lid closing action
From MEPIS Documentation Wiki
The action initiated by closing the lid of a laptop is controlled by KPowersave.
By default, closing the lid locks the screen. When the lid is raised again and any key is hit, a dialogue box pops up indicating the user's name who locked the screen and asking for that user's password to unlock it.
To stop the screen from being locked, right-click the KPowersave icon (plug or battery, depending on current power source). Click on "Configure KPowersave," then the tab "General Settings." Uncheck "Lock screen on lid close" and click "Apply."

