Hello Simon,

The tooltips appear when there is not enough room to display the text shown in the appointment timeslot area. This can easily be addressed by adding your own custom tooltip and handle the control's MouseEnterElement to show them.

void ultraDayView1_MouseEnterElement(object sender, Infragistics.Win.UIElementEventArgs e)
        {
            if (e.Element is Infragistics.Win.UltraWinSchedule.DayView.AppointmentUIElement)
            {
                Appointment appt = (Appointment)e.Element.GetContext(typeof(Appointment));
                Infragistics.Win.UltraWinToolTip.UltraToolTipInfo tti =
                    new Infragistics.Win.UltraWinToolTip.UltraToolTipInfo(appt.Subject, ToolTipImage.None, "",
                    DefaultableBoolean.True);
                ultraToolTipManager1.SetUltraToolTip(e.Element.Control, tti);
                ultraToolTipManager1.ShowToolTip(e.Element.Control);
            }
        }

Let me know if you have any questions regarding this matter.

Appointment tooltips are only displayed when the subject is not fully visible; if the appointment spans a whole day it is probably large enough to fully display the text, therefore the event does not fire.

Note that if you want to unconditionally show tooltips, you could use our UltraToolTipManager component.