Allow multiple docked views on one edge to be displayed at once. Add something like "layer" and "stackIndex" properties to each configured dock. The stackIndex property stacks from 0 at the edge, toward the center, allowing multiple docked views to be shown at the same time in any order. The layer property sets precedence that allows views to be stacked/cover eachother (0 and the bottom, moving up).

The motivation here is to have one permanent dock with small indication icons, and one onDemand dock with a handle that can cover over the permanent dock when expanded. So, the small icons draw attention to the collapsed dock, that can then be opened to see details about the notifications, without having to embed the same view on every view.