All the editing history is kept in Editing History. In image view | editing mode, click tab Editing History on the bottom of Editing Panel, you get the list of all your editing tracks.
To undo or redo editing, just find the editing you just made and click the step next to it to redo editing or previous one to undo the editing.
After undo or redo your editing, to save your editing, please click button Save in the toolbar on the top.
