Undo/Redo

Undo is a generalized capability for returning a program back to a state prior to the last edit operation.  Redo is the opposite of Undo and it effectively re-applies the last edit operation.  Undo can be applied repeatedly to erase the effects of  a sequence of edit operations up to a current limit of 20.  After performing a sequence of Undo operations, the same number of Redo operations are available. However, the instant a new edit is performed, the Redo list is cleared. 

• To undo an edit operation, select EditUndo from the main menu or press the button on the tool bar.
• To redo an edit operation, select EditRedo from the main menu or press the button on the tool bar.

Hovering the mouse over the button will display the name of the edit operation that would be "undone".  Similarly, hovering the mouse over the button will display the name of the edit operation that would be "redone".

Also, pressing the drop-down arrow will show a list of all the undo/redo's that are available. Clicking on one of those will undo/redo that item and all the ones above it.