Window >> Operation toolbar
OR
Tools >> Editor >> Undo/Redo operaton
The Undo and Redo tools are necessary when the user makes a mistake during the point cloud classification.
The Undo function cancel the last operations.
If too many operations are canceled, the Redo function allows you to restore the state before using the Undo option.
Hotkey: Tools.Undo
Hotkey: Tools.Redo