Thank you for contacting Telerik Support.
An easy and convenient way to achieve your first requirement would be to use:
scheduler = $find(
currentViewEndRange = scheduler.get_activeModel().get_visibleRangeEnd();
currentViewStartRange = scheduler.get_activeModel().get_visibleRangeStart();
//if appointment start time is before currentViewStartRange or after currentViewEndRange
scheduler.selectedDate() = appointment date
button in case of using AdvancedEditForm
following this CodeLibrary
or use client-side OnClientAppointmentEditing
Hope that this will lead you into right direction.
the Telerik team
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