jj: prevent opening of same window twice

app/DD-Record-Organizer/ModuleHelperMethods.vb

@@ -266,7 +266,12 @@ Module ModuleHelperMethods
 
     Public Sub OpenFormConstructor(id As Integer, Optional recordId As Integer = -1)
         Try
+            If CURRENT_OPEN_CONSTRUCTOR_FORMS.Contains(id) Then
+                Exit Sub
+            End If
+
             CURRENT_CONSTRUCTOR_ID = id
+            CURRENT_OPEN_CONSTRUCTOR_FORMS.Add(id)
             Dim frm As New frmConstructor_Main()
             ' frm = frmForm_Constructor.Instance()