[HOST] › blog › introducing-shadow-dom-api. When working with Shadow DOM-enabled components, the element is a web platform native way to allow content projection into components. 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. Try checking for existing elements in connectedCalback or by listening for slotchange events dispatched by your slot element ([HOST]Root. The slot is rendered correctly and everything appears to behave, except when flicking back and forth, once the earlier slot has been rendered. There are two kinds of slots: Named slots: