VOI definition is a tedious task, and many situations may occur where the user would like to undo a change. To this end an Undo/redo function for most manipulations of contour VOIs is available via the buttons.
The left arrow undoes operations (goes back through history), while the right button redoes operations (goes forward through history). The number of possible undo steps saved can be configured.
Note: The Undo function is not applicable to changes to the image information itself.