Potential fix for sortable.js + Polymer 2 to enable core config groups?

[gohassgo]

I'm not sure if this helps, but just ran across this sortable.is issue with a fork that "works fine except on phones."

SortableJS/Sortable#1237

[gohassgo]

SortableJS/polymer-sortablejs#35

[cgarwood]

Closing this since the frontend is on Polymer 3 now.