Set the selected block to upper case/lower case

Problem/Question/Abstract:

Set the selected block to upper case/lower case

Answer:

I constantly forget this shortcut, particularly the one how to set the selected block to lower case.
Since it is hard to find in the online help, here it is as a reminder for myself:

press Ctrl+K then release and press  O   block lower case
press Ctrl+K then release and press  N   block upper case

(I don't know whether this works in editor layouts other than IDE classic.)