There are multiple ways of undoing things. Save your project as a new project and use version numbers (like v1.001, V1.002 etc.) When making big changes. When you mess something up, simply copy the pattern from an older version to the new version. Use temp safe (func + yes) before making changes so you can revert back with func + no. Hold a parameter page button + no to revert that page back to saved state (also works on delay, reverb and master pages). When pasting or clearing a pattern, repeat that to undo it. When controlling all when you keep holding TRK press no to undo to the state before controll all.
That covers a lot 
and most of these are wonderful live performance tricks as well 
