Default PushButton in Container

<https://xojo.com/issue/34201>

If you have a default pushbutton that’s in a container where the visibility is being toggled, the default pushbutton top position changes after the first visible.

Example project is attached to Feedback report. Definitely an issue in Cocoa. Not sure about Carbon, Windows, or Linux.

I also see this in 2014r1.1 (Cocoa, not Windows VM).

Thanks, Bill!