Safely call WebPage.Show() from a page's Opening event

Allow a WebPage to safely call another page's Show() method from its Opening event.

This supports authentication gates, remembered-login routing and other startup decisions without requiring a Timer to defer navigation. The requested page should open after the current Opening event finishes, with predictable lifecycle ordering and no recursive page-transition error.

For example:

Class LoginPage Inherits WebPage
  Event Opening()
    If Session.IsAuthenticated Then
      Var searchPage As New SearchPage
      searchPage.Show()
    End If
  End Event
End Class