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In the Startup and Shutdown -> Background Services configuration applet make sure the Keyboard Daemon service ("Enables switching keyboard layout through shortcuts or system tray") is checked and in the "Running" state:

If this did not seem to have an effect, log out and back in. The settings should be applied afterwards.

For whatever reason this service is also responsible for propagating rate/delay changes to X11, which you can see live via:

watch -n1 'xset q | grep "auto repeat delay"' 

In the Startup and Shutdown → Background Services configuration applet, make sure the Keyboard Daemon service ("Enables switching keyboard layout through shortcuts or system tray") is checked and in the "Running" state:

If this does not seem to have an effect, log out and back in. The settings should be applied afterwards.

For whatever reason this service is also responsible for propagating rate/delay changes to X11, which you can see live via:

watch -n1 'xset q | grep "auto repeat delay"' 

Source: bcooksley's post at KDE Community Forums.

In the Startup and Shutdown -> Background Services configuration applet make sure the Keyboard Daemon service ("Enables switching keyboard layout through shortcuts or system tray") is checked and in the "Running" state:

[![Keyboard Daemon service screenshot][1]][1] [1]: https://i.sstatic.net/uHeN8.png

For whatever reason this service is also responsible for propagating rate/delay changes to X11, which you can see live via:

watch -n1 'xset q | grep "auto repeat delay"' 

In the Startup and Shutdown -> Background Services configuration applet make sure the Keyboard Daemon service ("Enables switching keyboard layout through shortcuts or system tray") is checked and in the "Running" state:

If this did not seem to have an effect, log out and back in. The settings should be applied afterwards.

For whatever reason this service is also responsible for propagating rate/delay changes to X11, which you can see live via:

watch -n1 'xset q | grep "auto repeat delay"' 

In the Startup and Shutdown -> Background Services configuration applet make sure the Keyboard Daemon ("Enables switching keyboard layout through shortcuts or system tray") is checked and in the "Running" state:

[![Keyboard Daemon service screenshot][1]][1] [1]: https://i.sstatic.net/uHeN8.png

For whatever reason this service is also responsible for propagating rate/delay changes to X11, which you can see live via:

watch -n1 'xset q | grep "auto repeat delay"' 

In the Startup and Shutdown -> Background Services configuration applet make sure the Keyboard Daemon service ("Enables switching keyboard layout through shortcuts or system tray") is checked and in the "Running" state:

[![Keyboard Daemon service screenshot][1]][1] [1]: https://i.sstatic.net/uHeN8.png

For whatever reason this service is also responsible for propagating rate/delay changes to X11, which you can see live via:

watch -n1 'xset q | grep "auto repeat delay"'