title: My computed property is not updating (composables)
body: <p>I'm starting to use Vue 3 and composables. However, it seems that the computed properties that depends on variables (or computed properties) in other composables are not updating.</p>
  <p>This is my first composable:</p>
  <pre class="lang-js prettyprint-override"><code>import { ref, computed } from 'vue'
  
  export default function useSum1() {
  
    const num1 = ref(2)
    const num2 = ref(3)
  
    // Simple sum
    const sum1 = computed(() =&gt; num1.value + num2.value)
  
    return {
      num1,
      num2,
      sum1
    }
  
  }
  </code></pre>
  <p>My second composable:</p>
  <pre class="lang-js prettyprint-override"><code>import { ref, computed } from 'vue'
  
  export default function useSum2 () {
  
    const num3 = ref(4)
    const num4 = ref(1)
  
    const sum2 = computed(() =&gt; num3.value + num4.value)
  
    return {
      num3,
      num4,
      sum2,
    }
  
  }
  </code></pre>
  <p>And my third composable, this one requieres sum1 and sum2 from the previous composables:</p>
  <pre class="lang-js prettyprint-override"><code>import { computed } from 'vue'
  import useSum1 from './useSum1'
  import useSum2 from './useSum2'
  
  const { sum1 } = useSum1()
  const { sum2 } = useSum2()
  
  export default function useSum3() {
  
    // This doesn't update when sum1 or sum2 changes, but works the first time
    const sum3 = computed(() =&gt; sum1.value + sum2.value)
  
    return {
      sum3
    }
  
  }
  </code></pre>
  <p>In App.vue:</p>
  <pre class="lang-js prettyprint-override"><code>import useSum1 from './composables/useSum1'
  import useSum2 from './composables/useSum2'
  import useSum3 from './composables/useSum3'
  
  const { num1, num2 } = useSum1()
  const { num3, num4 } = useSum2()
  const { sum3 } = useSum3()
  
  setTimeout(() =&gt; {
    num1.value = 3
  }, 2500)
  
  setTimeout(() =&gt; {
    num3.value = 5
  }, 5000)
  
  // sum3 is always 10, never updates
  </code></pre>
  <p>Thank you for any help.</p>