Combolist, addValue and Windows 2000

Hi !

I've got a problem with form comboList objects.
I use DesktopX Builder 3.1.
I can create a ComboList into a form, that works fine with Windows XP.
Under Windows 2000 (Pro SP4), the same list contains just one element when I launch the widget !

Is it a bug ?
Is there a way to make the combolists work under Windows 2000 ?

Here is a part of the code I use to create the list :
  frm.AddPreference("tailleWidget")
  frm.Preference("tailleWidget").Type = "comboList"
  frm.Preference("tailleWidget").Caption = "Widget size : "
  frm.preference("tailleWidget").addValue "Big"
  frm.preference("tailleWidget").addValue "Medium"
  frm.preference("tailleWidget").addValue "Normal"
  frm.preference("tailleWidget").addValue "Small"
  frm.preference("tailleWidget").defaultValue "Normal"

The list is ok with Windows XP but contains just "Normal" under Windows 2000... :/
I've got the same bad behavior with type="font"...

Thanks in advance for you help.
Happy new year.

Etienne.