Custom Element MutationObserver

I am not sure if this is related to uhtml or I am doing someting wrong. I am trying to attach a MutationObserver to a Custom Element with shadow DOM and watch for changes in the template (outside shadow DOM, not sure what the name is for this).

html`
  <custom-element>${someValue}</custom-element>
`

I am looking to catch re-render event and apply content changes to my shadow DOM.

I am attaching [non-]working pen to illustrate my issue: https://codepen.io/lemmonjuice/pen/rNMxxOw

When re-rendering the template nothing happens. However if I access the element directly and either change the textContent value or append a child the observer gets triggered. I was expecting that the re-render will trigger the observer as well. Checking the browser inspector I am seeing that the contetn was in fact updated properly.

Thanks.

[WebReflection]

You need childList too

[lemmon]

Okay, I guess I have figured it out. I need to pass combination of options:

{
  characterData: true,
  subtree: true,
}

Thank you!