First item sometimes disappears with ComponentRenderer

[pekam]

This is caused by iron-list. It has an extra focus element, which duplicates the content of the first item.
When you scroll down enough so that the iron-list reorders some of the item components, and then scroll back up, the component belonging to the first item may be rendered in the hidden focus element.

Making sure that the flow-component-renderer in the first item attaches the component, after the focus element has "stolen" the rendered component instance, would fix the issue.

An ugly workaround would be to disable the focus management by monkey-patching:

ironList._manageFocus = () => {}

The focus management might not be needed by combo-box, since it should not contain focusable elements like inputs.

A related ticket for iron-list: PolymerElements/iron-list#511