I've got a RadGantt that is both an AjaxControl and an AjaxUpdatedControl in a RadAjaxManager.
The control and the Ajax Updates work fine for everything except for deleting a task.
'Unable to get property 'oldUpdatePanelIDs' of undefined or null reference'
is coming from function _getPageLoadingEventArgs.
I don't understand why this doesn't happen all the time (or at all really), or why only on deletes. What would be different about the call or returned values based on the function? Anyone else seeing this behavior.