Hallo,
I'm using KDE Plasma 5.19.5 with Kate, Dolphin & Konsole and Klipper, of course. I just tried to use Klipper's action feature.
What I've reached, is that I could chose to start mpv in combination with the highlighted mp4 video, e.g. /mnt/NAS/Filme/King_Kong.mp4 .

What works, is that after highlighting, I have to press 'Ctrl + Alt +r ' to receive a (Klipper) menu, where I can click 'Execute Play video with mpv'.
In my Klipper's settings for the action to start 'mp4' files with 'mpv' I have selected 'automatic', but the menu does not appear automatically.

My question:
Is it possible to receive the menu without pressing 'Ctrl + Alt + r'? I would like (as I understood it), that the menu will appear automatically,
when Klipper recognizes a highlighted text with the regexp \.mp4$. The regexp is correct.

Thank you very much in advance,

-Linuxfluesterer

UPDATE: I have found the solution, I found it by random. There is a shortcut: 'Ctrl Alt x' , which is not only to be used to DISABLE actions on Klipper, to ENABLE I will need to enter 'Ctrl Alt x' also, but nothing indicates, actions are enabled or not. You can find this topic described here as a bug here:

http://bugs.kde.org/show_bug.cgi?id=409803