[VB]
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
　　GcCalendar1.SelectionMode = GrapeCity.Win.Calendar.SelectionMode.MultiSimple
End Sub

Private Sub GcCalendar1_SelectedDateChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles GcCalendar1.SelectedDateChanged
　　If GcCalendar1.Selections.Count > 1 Then
　　　　GcCalendar1.Selections.RemoveAt(0)
　　End If
End Sub

[C#]
private void Form1_Load(object sender, EventArgs e)
{
　　gcCalendar1.SelectionMode = GrapeCity.Win.Calendar.SelectionMode.MultiSimple;
}

private void gcCalendar1_SelectedDateChanged(object sender, EventArgs e)
{
　　if (gcCalendar1.Selections.Count > 1)
　　{
　　　　gcCalendar1.Selections.RemoveAt(0);
　　}
}