This command (selectable by pressing <esc>) can only be used for a few things :
Press <f9> or indicate the item will redo the last action, if it is redoable. Only some operations can be redone.
hit the item or press <+> to select the item. This will mean that with the next operation the original object will be kept. After usage of this status, it is reset. If you do not want this automatic reset, indicate the item with a do. Only selecting it again will reset the status again.
If it is indicated, the original object will be kept with any t ransformation. This means that a copy is created on which the transformation is done.
If you select an objects while Keep is indicated, the selected will be added to the current object, instead of replacing the last added object. Except when you use the lasso select, because that will select only the objects that lie inside the lasso.
When this is necessary for some reason, you can always redraw the screen by pressing <control-f2>.