3.7. Undo and Redo From Dia previous page next page 3.7. Undo and Redo Dia supports Undo and Redo on most operations. To undo an operation, press Ctrl+Z or select Edit->Undo from the diagram menu bar. To redo an operation, press Ctrl+Shift+Z or select Edit->Redo from the diagram menu bar. previous page start next page