I don't know what I did but now some keys from the keyboard are not typing the corresponding letter but move the cursor instead. The expected letter is typed if I press the fn key at the same time. With the shift key pressed the funny keys type numbers.
I've read about a similar issue where the numlock key was activated. There is no numlock on this keyboard. I've installed
run 'numlockx off' : no change! With
'numlockx on' : the funny keys type numbers.
I've tried rebooting off course: nope...
Here an image of the keyboard :