Note that when applying the restamp attribute to dom-if. A slot is a placeholder inside a web component that users can fill with their own markup (see Using templates and slots for more information). The slotted element appears, but then doesn't disappear when the dom-if becomes false. [HOST] › blog › introducing-shadow-dom-api. . Slots allow to show elements from light DOM in specified places of shadow DOM. The slot is rendered correctly and everything appears to behave, except when flicking back and forth, once the earlier slot has been rendered. When working with Shadow DOM-enabled components, the element is a web platform native way to allow content projection into components. 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. There are two kinds of slots: Named slots: