"..." in sort-order and sort-order-fallback="abc" breaks sort-order for everything in it's group.

[masterpi314]

The decision to do fallback-sorting in sort-option.js happens only based on a.groupIndex === lastGroupIndex, incorrectly ignoring a.propertyIndex === lastPropertyIndex, and thus sorting everything in the group containing "..." together as one. That check should be moved below the propertyIndex check below it (so as not to have to check b.propertyIndex), and have && a.propertyIndex === lastPropertyIndex added to it.