UI elements doesn't work inside the shadow DOM

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**Environment:**

- Elements version: 11.0.2

**Desktop (please complete the following information):**

- OS: [e.g. Windows 10] Windows 10
- Browser [e.g. chrome, safari] Chrome
- Version [e.g. 22] 83

**Smartphone (please complete the following information):**

- Device: [e.g. iPhone6]
- OS: [e.g. iOS8.1]
- Browser [e.g. stock browser, safari]
- Version [e.g. 22]

**Steps to reproduce the problem:**
create a custom element with shadow DOM enabled and put the UI element inside e.g. content explorer

**What is the expected behavior? (Screenshots can be helpful here)**
the ui element should be rendered

**What went wrong? (Screenshots, console logs, or HAR files can be helpful here)**
the ui element is throwing an error TypeError: this.rootElement is null

**Link to application or sample code:**
https://codepen.io/hrobarikt/pen/NWxNqOg

**If relevant, link to file (or attach file here)**

**Expected behavior**
working box ui elements in a web application that is built using web components with shadow DOM enabled

**Screenshots**
If applicable, add screenshots to help explain your problem.

**Additional context**
Add any other context about the problem here.