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?
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