Change event not firing on nested grids (resize, move...)

[ddowie]

Hi,

does "change" event work on nested grid items?
In my situation change event is triggered only when moving or resizing parent (1st level) grid items.

Steps to reproduce

`var items = [{"x":0,"y":0,"w":6,"id":"5352223231011-3142222-410151-132321-200104202021152022100","subGridOpts":{"children":[]}},{"x":6,"y":0,"w":6,"id":"133014223145-112141-4112121-120214-43422114222221410","subGridOpts":{"children":[{"id":"01344140020-1013320-4151323-1521411-1140103111252101411","subGridOpts":{"children":[]},"x":0,"y":0},{"id":"412141422121-102202-42145-12152321-5223321101112214225","subGridOpts":{"children":[]},"x":3,"y":0}]}},{"x":0,"y":1,"w":12,"id":"1122021332120-2201014-4151315-1521145-12102130152142222321","subGridOpts":{"children":[]}}];

let options = { // main grid options
resizable: {
handles: 'se'
},
margin: 8,
minRow: 2, // don't collapse when empty
acceptWidgets: true,
subGridDynamic: false,
subGridOpts: subOptions // all sub grids will default to those
};

var grid = GridStack.init(options);
grid.load(items);

grid.on('change', function (event, el) {
serializeFullGrid(grid);
});

`

[adumesny]

events are currently per grid and don't bubble up when nested. that is a feature request if you want to donate for it.