diff --git a/history_tree.py b/history_tree.py
index 4e35861..093d028 100644
--- a/history_tree.py
+++ b/history_tree.py
@@ -1,3 +1,4 @@
+import html
 import time
 import uuid
 from typing import Any
@@ -154,13 +155,14 @@ class HistoryTree:
             full_note = n.get('note', 'Step')
 
             display_note = (full_note[:max_note_len] + '..') if len(full_note) > max_note_len else full_note
+            display_note = html.escape(display_note)
 
             ts = time.strftime('%b %d %H:%M', time.localtime(n['timestamp']))
 
             # Branch label for tip nodes
             branch_label = ""
             if nid in tip_to_branches:
-                branch_label = ", ".join(tip_to_branches[nid])
+                branch_label = html.escape(", ".join(tip_to_branches[nid]))
 
             # COLORS — per-branch tint, overridden for HEAD and tips
             b_name = node_to_branch.get(nid)
@@ -190,7 +192,7 @@ class HistoryTree:
                 + '</TABLE>>'
             )
 
-            safe_tooltip = full_note.replace('"', "'")
+            safe_tooltip = full_note.replace('\\', '\\\\').replace('"', '\\"')
             dot.append(f'  "{nid}" [label={label}, tooltip="{safe_tooltip}"];')
 
             if n["parent"] and n["parent"] in self.nodes:
diff --git a/tab_batch_ng.py b/tab_batch_ng.py
index 857986f..f905cb3 100644
--- a/tab_batch_ng.py
+++ b/tab_batch_ng.py
@@ -608,7 +608,13 @@ def _render_sequence_card(i, seq, batch_list, data, file_path, state,
 
 def _render_vace_settings(i, seq, batch_list, data, file_path, state, refresh_list):
     # VACE Schedule (needed early for both columns)
-    sched_val = max(0, min(int(seq.get('vace schedule', 1)), len(VACE_MODES) - 1))
+    def _safe_int(val, default=0):
+        try:
+            return int(float(val))
+        except (ValueError, TypeError, OverflowError):
+            return default
+
+    sched_val = max(0, min(_safe_int(seq.get('vace schedule', 1), 1), len(VACE_MODES) - 1))
 
     # Mode reference dialog
     with ui.dialog() as ref_dlg, ui.card():
@@ -678,10 +684,10 @@ def _render_vace_settings(i, seq, batch_list, data, file_path, state, refresh_li
                 'outlined').classes('w-full q-mt-sm')
 
             # VACE Length + output calculation
-            input_a = int(seq.get('input_a_frames', 16))
-            input_b = int(seq.get('input_b_frames', 16))
-            stored_total = int(seq.get('vace_length', 49))
-            mode_idx = int(seq.get('vace schedule', 1))
+            input_a = _safe_int(seq.get('input_a_frames', 16), 16)
+            input_b = _safe_int(seq.get('input_b_frames', 16), 16)
+            stored_total = _safe_int(seq.get('vace_length', 49), 49)
+            mode_idx = _safe_int(seq.get('vace schedule', 1), 1)
 
             if mode_idx == 0:
                 base_length = max(stored_total - input_a, 1)
diff --git a/tab_timeline_ng.py b/tab_timeline_ng.py
index d0467f4..521d4da 100644
--- a/tab_timeline_ng.py
+++ b/tab_timeline_ng.py
@@ -13,6 +13,7 @@ def _delete_nodes(htree, data, file_path, node_ids):
     if 'history_tree_backup' not in data:
         data['history_tree_backup'] = []
     data['history_tree_backup'].append(copy.deepcopy(htree.to_dict()))
+    data['history_tree_backup'] = data['history_tree_backup'][-10:]
     for nid in node_ids:
         htree.nodes.pop(nid, None)
     for b, tip in list(htree.branches.items()):
diff --git a/utils.py b/utils.py
index 75269ab..0ec9fff 100644
--- a/utils.py
+++ b/utils.py
@@ -210,7 +210,8 @@ def sync_to_db(db, project_name: str, file_path: Path, data: dict) -> None:
                     now = time.time()
                     db.conn.execute(
                         "INSERT INTO sequences (data_file_id, sequence_number, data, updated_at) "
-                        "VALUES (?, ?, ?, ?)",
+                        "VALUES (?, ?, ?, ?) "
+                        "ON CONFLICT(data_file_id, sequence_number) DO UPDATE SET data=excluded.data, updated_at=excluded.updated_at",
                         (df_id, seq_num, json.dumps(item), now),
                     )