++paranoia;

libtaskmanager/tasksmodel.cpp

@@ -509,9 +509,15 @@ void TasksModelPrivate::itemMoved(AbstractGroupableItem *item)
 void TasksModelPrivate::itemChanged(::TaskManager::TaskChanges changes)
 {
     Q_UNUSED(changes)
+
     AbstractGroupableItem *item = static_cast<AbstractGroupableItem *>(q->sender());
     const int index = indexOf(item);
-    QModelIndex idx = q->createIndex(index, 0, item);
+
+    if (index == -1) {
+        return;
+    }
+
+    const QModelIndex idx = q->createIndex(index, 0, item);
     emit q->dataChanged(idx, idx);
 }