Undo/Redo Panel

This panel displays the number of changes you have applied to the picture during your editing.

You can undo the changes using the "Undo" button

You can repeat that changes using the "Redo" button

After the maximum number of "undo" steps is reached, the oldest undos will be replaced by the new ones. To increase the size of the undo buffer you can select from main menu:

Options->Number of Undo (Undo Buffer). By default you have 60 Undo Steps available for each new project.

Focus uses temporary files on your hard disk to store undo informations: this method has the big advantage of not consuming memory.