Private Declare Function SendMessage Lib "user32" Alias _
   "SendMessageA" _
   (ByVal hwnd As Long, ByVal wMsg As Long, _
    ByVal wParam As Long, lParam As Any) As Long
 
Private Declare Function FindWindowEx Lib "user32" Alias _
   "FindWindowExA" (ByVal hWnd1 As Long, ByVal hWnd2 As Long, _
    ByVal lpsz1 As String, ByVal lpsz2 As String) As Long
 
Private tmpComboInx As Integer
Private hWndEdit As Long
 
Private Const EM_SETSEL = &HB1
 
Private Sub Combo1_Click()
   tmpComboInx = Combo1.ListIndex
End Sub
 
Private Sub Combo1_KeyUp(KeyCode As Integer, Shift As Integer)
  If KeyCode = 32 Then
      Combo1.Text = Combo1.Text + Combo1.List(tmpComboInx)
      Combo1.Text = Replace(Combo1.Text, " ", "")
      SendMessage hWndEdit, EM_SETSEL, Len(Combo1.Text), 0&
   End If
End Sub
 
Private Sub Form_Load()
   Combo1.AddItem "+"
   Combo1.AddItem "-"
   Combo1.AddItem "."
   hWndEdit = FindWindowEx(Combo1.hwnd, 0, "Edit", "")
End Sub