If the only the center region in an axis is selected, or all three regions are selected, the default alignment in that axis is anchor-center.

I'm wondering if the default alignment in the center track should be center instead of anchor-center.

This makes a difference if the author applies asymmetric insets, e.g. given a 100px anchor, suppose there's a 10px inset on the right. Should the item be centered against the entire anchor, or against the inset area?

I suspect the answer should be the inset area, i.e. center. @kizu wdyt?