Customized built-in elements don't work when they're cloned from a <template> element

[serg-io]

The attached test.zip file contains an index.html file that tests adding custom elements (v1) using multiple methods.

Autonomous custom elements seem to work fine using all the methods to create and add them to the page.

However, customized built-in elements don't work when they're cloned from a element.

Here's the result I get using Chrome 54, 55, and 56:

Thank you in advance for looking into this issue.

[WebReflection]

the innerHTML case is special, as described in the README

The cloneNode seems to be fixed in non compliant browsers, I'll try to understand what is going on with Chrome.

Thanks

[WebReflection]

is this bug still relevant ?

[WebReflection]

no answers since May, not interested in solving this, not even sure it's still an issue so closing it for now.