ComboBox List Display 1 item at first click

anyone help me to solve the tiny problem of ComboBox List

if ComboBox List Contain 1 to 30 items and i click for first time it display 1 item only
click anywhere for deselect the combobox and
again click the List is full 1 to 30

why it not display the full list


see the attachments for more info.

Managed to get it running the first time round by using the DropButtonClick event instead of the GotFocus event.

Private Sub ComboBox1_DropButtonClick()
Dim i As Long
ComboBox1.Clear

For i = 0 To 30
    ComboBox1.AddItem i
Next i
End Sub