Dropdown is closing immediately when used inside Shadow DOM

[Nicolai8]

Hello.

I'm having an issue with chosen select used inside custom element (shadow DOM). When I click on input it should show the list but instead it's immediately closing list after showing it.

Steps to reproduce

1. create ES6 class and extend HTMLElement

2. create shadow and add select inside of it

3. apply chosen to that select

Codepen example

Expected behavior

List should be shown on input click

Actual behavior

List is shown for a second and then dissapears

Environment

Firefox 62.0.3 - 63.0,
Chrome 69.0.3497.100,
Windows 8.1 64Bit