Unity was a very sophisticated Project sadly it has to be dropped, but it has been picked up by a 12 year old, very impressive: Download or "sudo apt install ubuntu-unity-desktop" The most important thing is the Unity HUD, which can also be activated in Mate in Mate Tweaks, alongside with pulldown terminal alt+F12 and the Dock. Its the innovation for the PC from Cannonical, in gimp for instance i can find my menu entry in half a second instead of searching for a minute. Simply press the alt key then type the menu entrys name.
The Mutiny Layout or Cupertino under System Menu - Administration - Welcome - Desktop Layouts us very impressive. On the other hand the standard Layout Task Manager with Text is not very good to use.
Clipboard Manger: Dock left right click - add docklets - clippy or "sudo apt-get install diodon" then its a small clipper in the right upper left.
caja remove "revert to previous version" : preferences - extentions - dejadub remove checkbox reboot
If system panel is lost: Strg+Alt+T (terminal) "killall mate-panel"