Hey... toolbars and dialogs in your first attempt ;-)
After creating the "Addpos" dialog, you might find this is useful too:
It centers the dialog nicely.
Remember too, that if your dialog is going to be reasonably complicated, you could Extend from wxDialog with your own Type, and add control creation into its own OnInit() method. Otherwise you end up with lots of control creation in one place - I'm for keeping things grouped together :-p
After creating the "Addpos" dialog, you might find this is useful too:
Addpos.Center(wxBOTH)
It centers the dialog nicely.
Remember too, that if your dialog is going to be reasonably complicated, you could Extend from wxDialog with your own Type, and add control creation into its own OnInit() method. Otherwise you end up with lots of control creation in one place - I'm for keeping things grouped together :-p