A misplaced structure, an unwanted transformation, or an edit that takes a model in the wrong direction can interrupt your work. The first instinct is often to press Undo repeatedly—but when several operations have happened since the mistake, it helps to see the sequence rather than guess. SAMSON’s History view lets you inspect a document’s action history and move through its previous states.
Each SAMSON document has its own history. That distinction matters when you have more than one document open: the history you inspect belongs to the document you are working with, not to every document in the session. To open the view, choose Interface > History, or use Ctrl+3 on Windows or Linux and Cmd+3 on Mac.
Recover by inspecting, not guessing
When an edit produces an unexpected result, open History and look through the listed actions. You can click actions in the History view to move through document states. This gives you a way to inspect earlier points in the editing sequence instead of repeatedly undoing without knowing where you will end up.
You can also use the Edit menu’s Undo and Redo commands. The shortcuts are Ctrl+Z and Ctrl+Y on Windows and Linux, and Cmd+Z and Cmd+Y on Mac. Undo moves back through undoable actions; Redo moves forward again. If you undo too far, Redo can help you return to a later state, provided the action remains available in the history.
A cautious recovery routine
- Pause when the result looks wrong. Avoid making more edits until you have checked what happened; additional actions can make it harder to identify the change you want to reverse.
- Open the History view. Confirm you are looking at the history for the document you intend to correct.
- Review the actions around the problem. Use the listed actions to navigate through previous document states and identify a suitable point to return to.
- Use Undo or select an earlier state. If needed, proceed step by step and check the structure after each change.
- Redo carefully if you go too far. Redo lets you move forward again through available actions.
Why Undo may not be enough
Not every operation in SAMSON is undoable. The documentation warns that if non-undoable operations occur between undoable ones, SAMSON may not be able to undo the sequence properly, which can result in data loss. So the History view is a useful recovery aid, not a guarantee that every operation can be reversed.
For work you cannot afford to lose, a prudent habit is to save your document regularly and be especially careful after an operation that does not appear to reverse as expected. Before continuing with a long editing or building session, take a moment to check the state of the model. A few seconds of inspection can prevent an uncertain chain of Undo commands.
Whether you are building a molecule, moving structures, or testing transformations, treating history as a way to inspect and navigate—not simply as an emergency button—can make recovery more deliberate. Learn more in the SAMSON History documentation.
Note: SAMSON and all SAMSON Extensions are free for non-commercial use. Get SAMSON.