The redo command reverses the change made by the last undo command. A series of consecutive undos may be reversed by the corresponding number of redos. Redo operations do not get added to the undo buffer.

If you choose Edit > Undo several times and proceed to perform a new (non undo or redo) operation, the forward items in the undo buffer is discarded in favor of the new operation. In this case there would no longer be any operations to redo.

Example