diff --git a/web/app.js b/web/app.js
index 1afb48c..a874591 100644
--- a/web/app.js
+++ b/web/app.js
@@ -856,7 +856,7 @@ function renderTree() {
     <div class="task-node depth-${t.depth}">
       <div class="task-row ${isGate ? 'is-gate' : ''} ${expanded ? 'expanded' : ''} ${isCtx ? 'filter-ctx' : ''}" data-action="toggle-detail" data-id="${esc(t.id)}">
         ${caret}
-        <span class="t-title">${esc(t.title)}<span class="t-id">${esc(t.id.slice(-6))}</span></span>
+        <span class="t-title">${esc(t.title)}<span class="t-id">${esc(String(t.id || '').slice(-6))}</span></span>
         <span class="spacer"></span>
         ${(() => {
           // blocked（系统按依赖自动落位）→ 显示在等哪几条
@@ -1000,7 +1000,7 @@ function renderParentOptions() {
   const sel = document.querySelector('#newTaskPanel select[name=parentId]');
   const cur = sel.value;
   sel.innerHTML = `<option value="">（顶层）</option>` +
-    S.tasks.map((t) => `<option value="${esc(t.id)}">${esc('· '.repeat(t.depth - 1) + t.title)}</option>`).join('');
+    S.tasks.map((t) => `<option value="${esc(t.id)}">${esc('· '.repeat(Math.max(0, (t.depth || 1) - 1)) + t.title)}</option>`).join('');
   sel.value = cur;
 }