Ok Schutrman, I got the exact same result than our friend. So I followed exactly what you said and here is the result:

in the folder:
/home/user/.local/share/applications I have:

defaults.list
quicklauncherbar0.desktop
quicklauncherbar1.desktop
quicklauncherbar2.desktop
quicklauncherbar3.desktop
simatk.desktop

If I make the command with -R, the message is that I don't have the permission to make chown on each file inside applications (listed above).

Thanks for your help