So with a super basic TreeGrid and a remote dataManager that returns an empty dataset to start with, when you go to add your first item via the Add button, when you click save the following error is thrown in the console and the item is never sent to the server. As long as the dataset returns with at least 1 item, everything works as expected.
Uncaught TypeError: Cannot read property 'length' of undefined
at e.beginAddEdit (ej2.min.js?id=68729179e2599736a9df:1)
at e.beginEdit (ej2.min.js?id=68729179e2599736a9df:1)
at e.notify (ej2.min.js?id=68729179e2599736a9df:1)
at t.notify (ej2.min.js?id=68729179e2599736a9df:1)
at e.<anonymous> (ej2.min.js?id=68729179e2599736a9df:1)
at e.notify (ej2.min.js?id=68729179e2599736a9df:1)
at t.e.trigger (ej2.min.js?id=68729179e2599736a9df:1)
at t.grid.actionBegin (ej2.min.js?id=68729179e2599736a9df:1)
at e.notify (ej2.min.js?id=68729179e2599736a9df:1)
at t.e.trigger (ej2.min.js?id=68729179e2599736a9df:1)
Additionally, the spinner artifact remains after data is bound and needs to be removed via:
dataBound: function (args){
$('.e-spinner-pane.e-spin-show').remove();
},