The IntelliJ IDEA short-cut to reformat source code is Ctrl+Alt+L. This happens to lock the screen in KDE (Gnome too?). How can I disable this so IntelliJ receives the key sequence?
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