Nested grids demo

This example shows v5.x dragging between nested grids (dark yellow) and parent grid (bright yellow.)
Uses v3.1 API to load the entire nested grid from JSON.
Nested grids uses new column:'auto' to keep items same size during resize.

Add Widget Add Widget Grid1 Add Widget Grid2 entire save/re-create: Save Destroy Create partial save/load: Save list Save no content Clear Load