Focus order of pseudo-element scroll markers

[flackr]

What should the focus order of the generated scroll markers be? Currently what's implemented in the polyfill puts them immediately after the scrollable area, but the tree order for pseudo elements would usually place them immediately after their originating element.

there are a few options here:

1. Immediately before the scrollable area.
2. Immediately after the scrollable area.
3. In the order of their originating DOM elements.

I suspect that there are use cases where you would expect 1 (tab-like interfaces) or 2 (marker-like interfaces) depending on where visually the scroll markers appear.

This could be a little odd in that the only tabbable scroll marker, the active one, could be either before or after the content you have focused in the scroller.

[argyleink]

Also, the focus order of the next/prev buttons are in this tab flow too, should the buttons go before or after the markers or before or after the focusable scroller? do the a11y guidelines have any answers for us?