<Portal> doesn't inherit class and style

[xymopen]

We are using <Portal> to transfer some nodes to some location, with parent being display: flex. When more than one node is transferred, the wrapper <div> would prevent flexbox related CSS rules from working.
Currently we are using a random tag as custom element and display: contents as a workaround. However in some cases Vue would complain that as an unregistered component.
Making <Portal> inherits staticClass, class, staticStyle and style looks like a perfect fix from our point of view.

[sdussaut]

Can confirm that no HTML attributes seem (class and id are not) to be inherited (Vue default behaviour).