Thanks very much both,
It is very clear. I disabled the Lock as suggested and it is working well now.

Hello, I am a beginner so sorry if my question is addressed elsewhere, but I did not manage to find any clue anywhere. There is a lock key on my keyboard. I do not manage to identify it or to remap it properly. Using Key History, it shows when I click on it : 5B 15B d 124.55 LWin 4C 026 d 0.00 l 5B ...