Undo and Redo
The Undo and Redo options allow you to either erase the last change made to
the .REQ (Undo) or reverse the effect of the undo action (Redo).
Note: The limit to undo is 1,000 operations. The number of text
changes inside a cell on one of the grid tabs is unlimited, but once you exit that
cell the undo history is gone.