Disable global Ctrl-Alt-L hotkey in KDE

Question

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.

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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

On Kubuntu 11.10 it's well hidden:

1. Start System Settings
2. Under Common Appearance and Behavior, select Shortcuts and Gestures.
3. Select Global Keyboard Shortcuts in the left-hand panel.
4. Select the KDE Component: Run Command Interface (important, otherwise you won't see the ctrl-alt-L mapping!)
5. Select Lock Session
6. Edit the setting, either choose a different mapping or 'none'.

I eventually found how to disable the lock screen key binding (Ctrl-Alt-L) in the System Setting app.

System Settings->"Keyboard Mouse->Keyboard Shortcuts

I had to choose the KDE component: Run Command Interface.

I'm running KDE on Fedora Core 9.

For Linux Mint: System Settings -> Keyboard -> Keyboard Shortcuts -> System -> Lock screen

It's easy to disable all global keyboard shortcuts in KDE for specific applications. I've done it in KDE 4 and now I've done it in KDE 5 again. So in KDE 5 right click on your application's window title -> More actions -> Special Window Settings (or Special Application Settings) -> Appearance & Fixes -> Ignore Global Shortcuts -> Force, Yes. It's much easier than to look for each shortcut one by one.

You can check such configurations in System Settings -> Window Management -> Window Rules.

Instead of disabling anything, you can also use ctrl+meta+alt+l in most applications where this problem exists. KDE knows the meta key (aka the 'windows key'), but the applications seem to ignore it and consider it to be just ctrl+alt+l.