diff --git a/crates/engine/src/interaction_rollback_tests.rs b/crates/engine/src/interaction_rollback_tests.rs
new file mode 100644
index 000000000..3a7380170
--- /dev/null
+++ b/crates/engine/src/interaction_rollback_tests.rs
@@ -0,0 +1,67 @@
+//! A command that fails part-way (a property that applies, then one that doesn't) leaves nothing
+//! behind — also during an interaction, whose last valid preview and own snapshot survive it.
+
+use serde_json::json;
+
+use crate::Session;
+use crate::params::id_of;
+
+fn rect(s: &mut Session) -> crate::NodeId {
+    id_of(&s.execute("shape.rectangle", &json!({"x": 0, "y": 0, "width": 80, "height": 60})).unwrap()["id"]).unwrap()
+}
+
+/// `width` applies (geometry keys go first), then `visible` fails validation.
+fn partially_applicable(s: &mut Session, id: crate::NodeId) -> crate::Result<serde_json::Value> {
+    s.execute("node.set", &json!({"id": id, "width": 123, "visible": "yes"}))
+}
+
+#[test]
+fn a_failed_command_during_an_interaction_keeps_the_prior_preview() {
+    let mut s = Session::new();
+    let r = rect(&mut s);
+    s.begin_interaction("Move").unwrap();
+    let props = serde_json::Map::from_iter([("x".to_string(), json!(20.0))]);
+    s.preview(|d, _| crate::cmd::props::apply("node.set", d, r, &props)).unwrap();
+    let (previewed, selection, page) = {
+        let ds = s.ds().unwrap();
+        (ds.doc.clone(), ds.selection.clone(), ds.page)
+    };
+    let before_journal = s.journal.clone();
+    let before_history = s.ds().unwrap().history.undo.len();
+
+    assert!(partially_applicable(&mut s, r).is_err());
+
+    // The rejected edit is gone: the command-entry state (the valid preview) is back.
+    let ds = s.ds().unwrap();
+    assert_eq!(*ds.doc, *previewed, "the document is what the preview showed");
+    assert_eq!(ds.doc.node(r).unwrap().width, 80.0);
+    assert_eq!(ds.selection, selection);
+    assert_eq!(ds.page, page);
+    assert_eq!(ds.history.undo.len(), before_history);
+    assert_eq!(s.journal, before_journal);
+
+    // The interaction is alive and commits the preview, not the rejected mutation.
+    s.commit_interaction().unwrap();
+    let n = s.doc().unwrap().node(r).unwrap();
+    assert_eq!((n.width, n.visible), (80.0, true));
+    assert_eq!(n.transform.as_coeffs()[4], 20.0, "the previewed move is committed");
+    assert_eq!(s.undo_depth(), (before_history + 1, 0));
+    assert_eq!(s.undo_labels(1), vec!["Move".to_string()]);
+    s.undo().unwrap();
+    assert_eq!(s.doc().unwrap().node(r).unwrap().transform.as_coeffs()[4], 0.0);
+}
+
+#[test]
+fn a_failed_command_without_an_interaction_still_rolls_back() {
+    let mut s = Session::new();
+    let r = rect(&mut s);
+    let before_journal = s.journal.clone();
+    let before_history = s.ds().unwrap().history.undo.len();
+
+    assert!(partially_applicable(&mut s, r).is_err());
+
+    let n = s.doc().unwrap().node(r).unwrap();
+    assert_eq!((n.width, n.visible), (80.0, true));
+    assert_eq!(s.ds().unwrap().history.undo.len(), before_history);
+    assert_eq!(s.journal, before_journal);
+}
diff --git a/crates/engine/src/lib.rs b/crates/engine/src/lib.rs
index 7ea8b52b6..cae7e5e71 100644
--- a/crates/engine/src/lib.rs
+++ b/crates/engine/src/lib.rs
@@ -846,10 +846,11 @@ impl Session {
                 }
             }
             Err(_) => {
-                // Roll back any partial edit.
+                // Roll back any partial edit — also during an interaction, where `before` is the
+                // interaction's last valid preview: restore it and leave the gesture itself (its
+                // own snapshot) alone.
                 if let Some((doc, sel, page, uid)) = before
                     && let Some(ds) = self.docs.iter_mut().find(|d| d.uid == uid)
-                    && ds.interaction.is_none()
                 {
                     ds.doc = doc;
                     ds.selection = sel;
@@ -1491,6 +1492,8 @@ mod import_export_tests;
 #[cfg(test)]
 mod inspect_behaviour_tests;
 #[cfg(test)]
+mod interaction_rollback_tests;
+#[cfg(test)]
 mod invite_links_tests;
 #[cfg(test)]
 mod keymap_tests;