Many Manifold commands can be undone using the Undo button. The keyboard shortcut for Undo is CTRL-Z.
Once undone with Undo, a command may be redone with Redo. The keyboard shortcut for Redo is CTRL-Y.
The Undo command will undo the last issued command. In some cases, Manifold will allow undoing more than one command, but usually it is only the last command that can be undone.
Very important: Not all commands and operations in Manifold may be undone. Routine image editing and drawing editing commands, transform operators, selections, copy and paste operations, renaming and other commands can in general be undone. However, some operations with tables and external tables linked into a Manifold project may or may not be undone. Even simple changes to tables if they are linked to an external data provider might not be undoable if the external provider does not support undo. Before making sweeping changes to tables, please take time to make a copy of the table data by exporting it to a file.
Some Undo actions require making transient copies of data to allow the action to be undone. Certain operations can involve lots of data and thus result in slower performance than desired because of the time required for copying transient data. Manifold provides two options in the Tools - Options - Confirmations page to control this behavior:
· Confirm creating undo actions larger than  MBytes
· Never create undo actions larger than  MBytes
The sizes used in the above options are user settable, with 50 and 250 MB the respective defaults.
The CTRL-Z keyboard shortcut for Undo is frequently used with editing when operating with the mouse with one hand and commanding cut, copy and paste commands with CTRL-X, CTRL-C and CTRL-V keyboard shortcuts to reverse unintended keyboard commands.