This article explains how you can use the and elements to create a flexible template that can then be used to populate the shadow DOM of a. To access children assigned to slots in your shadow root, you can use the standard [HOST]edNodes or [HOST]edElements methods with the slotchange event. Try checking for existing elements in connectedCalback or by listening for slotchange events dispatched by your slot element ([HOST]Root. The slotted element appears, but then doesn't disappear when the dom-if becomes false. The slot is rendered correctly and everything appears to behave, except when flicking back and forth, once the earlier slot has been rendered. As you can see, slot-based composition is a powerful tool that allows widgets to pull in the page content without cloning or modifying the DOM. . There are two kinds of slots: Named slots: