message: remove reference to refElm after initial patch (fix
diff: @@ -65,6 +65,9 @@ export function lifecycleMixin (Vue: Class<Component>) {
  vm.$options._parentElm,
  vm.$options._refElm
  )
  + // no need for the ref nodes after initial patch
  + // this prevents keeping a detached DOM tree in memory (#5851)
  + vm.$options._parentElm = vm.$options._refElm = null
  } else {
  // updates
  vm.$el = vm.__patch__(prevVnode, vnode)
  @@ -129,8 +132,6 @@ export function lifecycleMixin (Vue: Class<Component>) {
  if (vm.$el) {
  vm.$el.__vue__ = null
  }
  - // remove reference to DOM nodes (prevents leak)
  - vm.$options._parentElm = vm.$options._refElm = null
  }
  }
  