Select On if you want to be able to undo operations.
This is the default.
Queue
Select
Infinite to perform an unlimited number of undo operations. This
option can use a lot of memory. Select Finite to limit the number
of undo operations you can perform (specified in the Queue
Size box). The default is Finite.
Queue size
If Finite is the selected Queue setting,
specify here the number of undo operations you can perform. The
default is 50.
