Thank you for contacting Syncfusion support.
We have prepared the sample to disable the alert window while editing/deleting the recurrence appointment which can be viewed from the below link.
<Code>
function onCreate(args) { // this function will be called during the initial load
if (ej.isNullOrUndefined(this._alertWindow) && ej.isNullOrUndefined(this._recurEditWindow)) {
this._renderRecurEditWindow();
this._renderAlertWindow();
}
this._alertWindow.ejDialog({ beforeOpen: "onBeforeOpen" });
this._recurEditWindow.ejDialog({ beforeOpen: "onBeforeOpen" });
}
function onBeforeOpen(args) {
var obj = $("#Schedule1").data("ejSchedule")
$("#" + obj._id + "RecurrenceEdit_wrapper").addClass("csutom");
}
<style>
.csutom {
display: none !important;
}
</style>
</Code>
While openeing an alert window, no event will be raised which is the default behavior. Its not a bug.
Regards,
Karthigeyan