paper-radio-button nested in custom element goes unnoticed

[AimForNaN]

Problem

I have a paper-radio-button nested within a custom element. I expected the button to be picked up by paper-radio-group, but it was not caught. I've been able to narrow it down to the call to queryDistributedElements() in _updateItems() of the IronSelectableBehavior (https://github.com/PolymerElements/iron-selector/blob/master/iron-selectable.html#L272). Changing queryDistributedElements() to querySelectorAll() would quickly solve the issue, but I know IronSelectableBehavior is used in more than one place and that might have undesirable effects.

I have made a custom element mimicking paper-radio-group, applying the aforementioned solution to its _updateItems() method, and it works.

Live Demo

https://jsfiddle.net/vbkpmat4/

As you can see, the third item is not considered part of the list.

Browsers Affected

All.

[notwaldorf]

Yeah, unfortunately this is a known limitation of iron-selector: PolymerElements/iron-selector#42 😰

Closing this as a duplicate of that issue.