You can undo the performed operations, or return to the previous status.
1) Click [Undo] of the timeline.
Executed operations are undone, and the timeline cursor and the In and Out points return to their original positions.
Undoing operations: [Ctrl] + [Z]
Click the [Undo] list button to display a history of operations executed so far, and select the operation to undo. This history is saved for each individual sequence.
Though the number of undos is basically unlimited, the history will be deleted starting with the oldest record if the system runs out of memory.