Undo Toolkit allows you to add unlimited undo and redo to your REALbasic project with just one line of code per control. Just change each control's "super" to its Undo Toolkit counterpart, add one line to set the EditUndo menu text, and you've implemented a fully featured undo system in a fraction of the time.
The Undo Toolkit includes window classes that automatically prompt the user to save changes (using a Mac OS X sheet window), manage the Mac OS X Aqua change flag, enable and handle the FileSave, EditUndo and EditRedo menu items, and support unlimited levels of undo with unlimited numbers of controls. Undo Toolkit supports application-wide or window-specific undo, you can choose the undo solution that's right for your project, and provides customizable language constants for multi-lingual apps.
(As featured in Issues 1.2 and 1.4 of REALbasic Developer magazine. RBD subscribers can download the tutorial files from the subscribers-only Web site.)