Disable global Ctrl-Alt-L hotkey in KDE
On Kubuntu 11.10 it's well hidden:
- Start System Settings
- Under Common Appearance and Behavior, select Shortcuts and Gestures.
- Select Global Keyboard Shortcuts in the left-hand panel.
- Select the KDE Component: Run Command Interface (important, otherwise you won't see the ctrl-alt-L mapping!)
- Select Lock Session
- Edit the setting, either choose a different mapping or 'none'.
Under the K menu, go to the Control Center.
Regional & Accessibility | Keyboard Shortcuts | Shortcut Schemes tab, Global Shortcuts tab.
In the search box, type "lock", which should narrow the visible shortcuts and show the Ctrl+Alt+L one ("Lock Session").
Underneath, click None.
Click the Apply button.
On KDE Plasma 5 go to System Settings | Desktop Behaviour | Screen Locking
Here you will find a "Keyboard Shortcut" option. Change it to something else or set to none