Gnumeric allows a default of 50 undo operations. If you are an advanced user, working on a. machine with limited resources, this can reduce the amount of resources available for other applications, and for Gnumeric itself, particularly if you are going to be working with a lot of charts. Fifty undo operations is far more than is necessary for run of the mill work, and if you are going that far back into history, chances are that you are doing something terribly wrong to begin with. Reducing the number of undo operations to about 20, or even 15, significantly improves the smoothness of your work, and does not take up unnecessary memory.