Layer
Overview
A Layer is a technical component that does not have specific Design guidance.
Layers are used to render content outside of a DOM tree, at the end of the document. This allows content to escape traditional boundaries caused by "overflow: hidden" css rules and keeps it on the top without using z-index rules. This is useful for example in ContextualMenu and Tooltip scenarios, where the content should always overlay everything else.
Variants
Basic layered content
Using LayerHost to control projection
In some cases, you may need to contain layered content within an area. Create an instance of a LayerHost along with an id, and provide a hostId on the layer to render it within the specific host. (Note that it's important that you don't include children within the LayerHost. It's meant to contain Layered content only.)