Getting An Other File Extension As Default Instead Of All Files As Default Extension?

I am using VB 08 running an openfiledialogue wanting to get the result of the GDS file (*.gds) to be the default extension at the drop down menu instead of All file when the openfiledialogue box opens.

I coded it with:

OpenFileDialogue.Filter = "GDS File(*.gds)|*.gds|All files|*.*"

but the results i get in the open file dialogue box remains as all files being in the drop down menu as the default file extension. How to i set it to ".gds" format?