title: VueJS code - wrong behavor - whats wrong?
body: <p>I have this code in VueJs , simple task list, completed and incompleted ones, when I check or uncheck the box the task should move to the proper list.</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>var app = new Vue({
    el: '#vueapp',
    data: {
      tasks: [{
          id: 1,
          description: 'Do some Stuff',
          completed: false
        },
        {
          id: 2,
          description: 'Go to pharmacy',
          completed: false
        },
        {
          id: 3,
          description: 'Go to doctor',
          completed: true
        },
        {
          id: 4,
          description: 'Do some Slask',
          completed: false
        },
      ]
    },
    methods: {
      toggleTask(key) {
        this.tasks[key].completed = !this.tasks[key].completed;
      }
    },
    computed: {
      incompleteTasks() {
        return this.tasks.filter(task =&gt; !task.completed);
      },
      completedTasks() {
        return this.tasks.filter(task =&gt; task.completed);
      },
    }
  });</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"&gt;&lt;/script&gt;
  &lt;div id="vueapp"&gt;
    &lt;h2&gt;Completed Tasks&lt;/h2&gt;
    &lt;ul&gt;
      &lt;li v-for="(task, key) in completedTasks"&gt;{{ task.description }}&lt;input type="checkbox" v-model="task.completed"&gt;&lt;/li&gt;
    &lt;/ul&gt;
  
    &lt;h2&gt;Incomplete Tasks&lt;/h2&gt;
    &lt;ul&gt;
      &lt;li v-for="(task, key) in incompleteTasks"&gt;{{ task.description }}&lt;input type="checkbox" v-model="task.completed"&gt;&lt;/li&gt;
    &lt;/ul&gt;
  &lt;/div&gt;</code></pre>
  </div>
  </div>
  </p>
  
  <p>tested in Chrome. Try check the first incomplete task , it moves on the upper list succesfully, but the next incomplete task gets checked too.!!!!</p>