double click to bring up form

I'm using a little sub routine to bring up a pop up calendar when i click in a cell, everythings lovely but it annoyingly comes up when i select a clolumn or row that also contains that cell.

Can anybody suggest a modification to require a double click to display the calendar?

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
    If Not Intersect(Target, Range("b2:b500")) Is Nothing Then frmCalendar.Show_Cal
End Sub

Regards

Paul