Built-in row dragging - managed, unmanaged, drop zones, grid-to-grid

[bmarkov]

Row reordering is doable in user-land today (demo 105 covers the single-grid case), but a proper built-in would handle the messy parts: managed vs unmanaged ordering, drop zones, and dragging rows between two grids.

Curious whether grid-to-grid dragging is something people actually need, or if single-grid reorder covers most cases for you.