It's handy to know that the panel can be locked in order not to delete launchers or panel by mistake (and you have to do it again from scratch).
Once locked, if you right-click on launchers or panel, the menu option "remove" does not appear, so you can not accidentally click on and the panel will not allow any changes to the configuration.
Of course, to do maintenance (move and create launchers, see properties, create / delete panels …) it must be unlocked.
Edit menus → Preferences → New menù → write “Panel” in Directory Properties ->Ok
then click on Panel → New Item ->Ok
→ in Create Launcher
Command: gsettings set org.mate.panel locked-down true
Now make the UNLOCK launcher
Command: gsettings set org.mate.panel locked-down false
Choose icons with lock-unlock emblems
In this way lock and unlock the panel becomes fast!
gsettings guide http://askubuntu.com/questions/22313/wha...o-i-use-it