You can redo canceled operations that have been executed by undo.
1) Click [Redo] of the timeline.
Executed operations are undone, and the timeline cursor and In and Out points are repositioned.
Redoing canceled operation: [Ctrl] + [Y], [Shift] + [Ctrl] + [Z]
Click the [Redo] list button to display a history of operations undone so far, and select an operation to redo. This history is saved for each individual sequence.