Combobox not diplaying properly!!

[Eva]

Hello,

I have a combobox on my form that will contain a list of
items when the combobox is clicked.

I have used the following code in the comboBox's click
event to add the items:

Private Sub CBoxDisCaraNames_Click(ByVal sender As Object,
ByVal e As System.EventArgs) Handles CBoxDisCaraNames.Click

If CBoxDisCaraNames.Items.Count = 0 Then
'load the caravan combobox with caravan names
Dim Cn As New SqlConnection("data
source=PARAGLAPTOP\VSdotNET;initial
catalog=CaravanDBLapSQLServ;integrated
security=SSPI;persist security info=False;workstation
id=PARAGLAPTOP;packet size=4096")
Dim cmd As New SqlCommand("SPSelCaraModels", Cn)
cmd.CommandType = CommandType.StoredProcedure

Try
Cn.Open()
Dim reader As SqlDataReader
reader = cmd.ExecuteReader()
While reader.Read
CBoxDisCaraNames.Items.Add
(reader.GetSqlString(0))
End While
Catch ex As Exception
MsgBox(ex.Message)
Finally
Cn.Close()
End Try
End If

End Sub
the problem i am having is that when the items are first
loaded into the combobox a full list is not displayed.
Onl;y a single item is shown!! However i can access the
other items by pressing on the 'up and down' arrows that
appear next to the single item.
When i click on the list a second time, the full list is
diplayed like a normal combobox!!

This strange behavious only seems to occur when the items
are first loaded.

does anyone know how i can stop this from happening??