PROJECT DESCRIPTION
This example demonstrates how to show a LoadingPanel when saving the Spreadsheet.
The Save method of the Spreadsheet fires a callback to the server, which is not caught by the PageRequestManager and RadAjaxManager. That is why, even though the Spreadsheet is AJAX-enabled, no loading panel is displayed when saving.
One workaround for this issue is overriding the save and _onCallbackResponse methods of the RadSpreadsheet and show/hide a Loading panel manually as described in the Show and Hide AjaxLoadingPanel explicitly article.