This action allows making multiple-action bindings into an atomic
operation that will be undone by a single Undo command. For example,
to optimize rat lines, you'd delete the rats and re-add them. To
group these into a single undo, you'd want the deletions and the
additions to have the same undo serial number. So, you
An alternative mechanism is freeze/unfreeze for the case restoring between
every two actions is not possible or not practical. The sequence is
Arguments:
Save | Saves the undo serial number. |
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Restore | Returns it to the last saved number. |
Close | Sets it to 1 greater than the last save. |
Block | Does a Restore if there was nothing to undo, else does a Close. |
Freeze | Make sure no subsequent actions will bump the undo serial |
UnFreeze or Thaw | Allow subsequent actions to bump the undo serial again |